Comparison of the Natural Humoral Antitumor Reactivity of Different Strains of Mice

Normal serum from C3Hf mice showed a complement-dependent cytotoxic reactivity against EL4 lymphoma cells, starting from 2 to 3 months of age, whereas normal serum from BALB/c and C57BL/6J mice became reactive only at a later age. The cytotoxins of normal sera of the 3 strains, as well as of a C57BL antiembryo antiserum studied in parallel, belong to the IgM class. When absorption tests were performed, using a variety of absorbing cells, marked differences were found among the sera, which according to their behavior could be divided in two groups: one group comprises the BALB/c and the C57BL sera, the other group the C3Hf serum from both young and old mice and the antiembryo antiserum. The reactivity of the 3 latter sera seems to be directed against specificities related to an ecotropic N-tropic virus, which on the contrary did not seem to be involved in the reactivity of BALB/c and C57BL sera. The C57BL antiembryo antiserum obtained by immunization with C3Hf embryos behaved differently from the C57BL normal serum and similarly to the C3Hf normal serum.

Collagen type II (CII)-specific antibodies induce arthritis in the absence of T or B cells but the arthritis progression is enhanced by CII-reactive T cells

Antibodies against type II collagen (anti-CII) are arthritogenic and have a crucial role in the initiation of collagen-induced arthritis. Here, we have determined the dependence of T and B cells in collagen-antibody-induced arthritis (CAIA) during different phases of arthritis. Mice deficient for B and/or T cells were susceptible to the CAIA, showing that the antibodies induce arthritis even in the absence of an adaptive immune system. To determine whether CII-reactive T cells could have a role in enhancing arthritis development at the effector level of arthritis pathogenesis, we established a T cell line reactive with CII. This T cell line was oligoclonal and responded to different post-translational forms of the major CII epitope at position 260-270 bound to the Aq class II molecule. Importantly, it cross-reacted with the mouse peptide although it is bound with lower affinity to the Aq molecule than the corresponding rat peptide. The T cell line could not induce clinical arthritis per se in Aq-expressing mice even if these mice expressed the major heterologous CII epitope in cartilage, as in the transgenic MMC (mutated mouse collagen) mouse. However, a combined treatment with anti-CII monoclonal antibodies and CII-reactive T cells enhanced the progression of severe arthritis.

The central nervous system-specific myelin oligodendrocytic basic protein (MOBP) is encephalitogenic and a potential target antigen in multiple sclerosis (MS)

Uncovering primary target antigens in multiple sclerosis (MS) is of major significance for understanding the etiology and pathophysiology of the disease, and for designing immunospecific therapy. In this study, a synthetic peptide representing a predicted T cell epitope on myelin oligodendrocytic basic protein (MOBP) was found to be encephalitogenic in C3H.SW mice, inducing experimental autoimmune encephalomyelitis with an abrupt onset. Two separate preliminary studies with MOBP peptides indicated that autoreactivity to MOBP occurs in MS. These data strongly suggest that MOBP is a highly relevant target in MS and further point to the complexity of antigen specificities in MS.

Immunological characterization of C3H mice congenic for Fas(lprcg), C3h/HeJ-Fas(lprcg)/Fas(lprcg)

Fas(lpr) (lpr) and Fas(lprcg) (lpr(cg)) are allelic mutations of the Fas gene that is involved in apoptosis or programmed cell death. Lpr greatly reduces the expression of functional Fas and lpr(cg) expresses the death domain-disabled, non-functional Fas on the cell surface. C3H/HeJ mice congenic for lpr(cg) (C3H-lpr(cg)) were established and compared with C3H/HeJ-lpr/lpr (C3H-lpr) mice for their immunological and pathological features. Lymphadenopathy, splenomegaly, development of CD4- CD8- B220+ or double-negative (DN) T cells, renal pathology, and lymphoid cell infiltration in the lung and liver were not significantly different between C3H-lpr(cg) and C3H-lpr mice. Noticeably, however, the production of serum immunoglobulin, autoantibodies against double-strand DNA and serum immune complexes were significantly lower in C3H-lpr(cg) than in C3H-lpr mice. The results indicate that the death signal through the death domain of Fas is responsible for lymphoproliferation due to the accumulation of DN T cells and suggest that the region of Fas outside the death domain may be involved in autoantibody production. The newly-developed congenic C3H-lpr(cg) mice will provide a powerful tool for research into the function of Fas apart from apoptosis.

Cutting edge: functional characterization of the effect of the C3H/HeJ defect in mice that lack an Lpsn gene: in vivo evidence for a dominant negative mutation

A point mutation in the Tlr4 gene, which encodes Toll-like receptor 4, has recently been proposed to underlie LPS hyporesponsiveness in C3H/HeJ mice (Lpsd). The data presented herein demonstrate that F1 progeny from crosses between mice that carry a approximately 9-cM deletion of chromosome 4 (including deletion of LpsTlr4) and C3H/HeJ mice (i.e., Lps0 x Lpsd F1 mice) exhibit a pattern of LPS sensitivity, measured by TNF activity, that is indistinguishable from that exhibited by Lpsn x Lpsd F1 progeny and whose average response is "intermediate" to parental responses. Thus, these data provide clear functional support for the hypothesis that the C3H/HeJ defect exerts a dominant negative effect on LPS sensitivity; however, expression of a normal Toll-like receptor 4 molecule is apparently not required.

Natural resistance to Mycoplasma pulmonis infection in mice: host resistance gene(s) map to chromosome 4

Strains of mice differ greatly in resistance to infection in their lungs with virulent Mycoplasma pulmonis (MP) organisms even during the first 5 days, prior to detection of humoral or T cell mediated acquired immune responses. C57BL/6 mice are resistant, and BALB/c and C3H mice are susceptible, and one major gene, MP, not linked to the H2 major histocompatibility complex, regulates resistance. C57BL/6 x C3H (B x H) and BALB/c x C57BL/6 (C x B) recombinant inbred strain mice were infected intratracheally with the T2 strain of MP. Five days later, the recovery of organisms from tracheolung lavages and lung tissue was determined. The strain distribution pattern of resistance indicated that the MP gene maps to chromosome 4. B6.C-H18 (B6 mice congenic for the BALB/c H18 gene of chromosome 4) were much more susceptible than B6 mice, but were less susceptible than BALB/c mice, supporting the data obtained with the recombinant inbred strain mice, but suggesting that other genes may also influence resistance to infection with MP.

The effect of blood transfusion on susceptibility to bacterial infection in genetically defined mouse models

BACKGROUND

Blood transfusions suppress immune function and increase susceptibility to infection, but the effects are not consistent.

STUDY DESIGN AND METHODS

Genetically defined mouse strains with the same or different haplotypes were used as blood transfusion recipients and donors. Transfused animals were subjected to cecal ligation and puncture (CLP) and followed for survival or were injected intravenously with Candida albicans to follow clearance of the Candida from the kidneys.

RESULTS

BALB/c (H-2d) mice transfused with C3H/HeJ (H-2k) or DBA/2 (H-2d) blood followed by CLP showed significantly lower survival (7 and 10%) than mice transfused with syngeneic blood (61%) or saline controls (56%). Lower survival was also observed in C3H/HeJ (H-2k) mice transfused with BALB/c (H-2d) blood and subjected to CLP (25%) compared with syngeneic transfusion (80%) or saline controls (70%). C57BL/6J (H-2b) mice showed minimal increases in mortality after CLP after transfusion with blood from C3H/HeJ (H-2k) (60% survival), DBA/2 (H-2d) (70% survival), or BALB/c (H-2d) mice (90% survival). When C. albicans was infused intravenously into transfused mice, a similar pattern of altered resistance to infection was found.

CONCLUSION

The ability of blood transfusions to increase susceptibility to bacterial infection appears to be dependent on genetic factors unrelated to the major haplotype.

Chronic Pseudomonas aeruginosa lung infection is more severe in Th2 responding BALB/c mice compared to Th1 responding C3H/HeN mice

The chronic Pseudomonas aeruginosa lung infection in cystic fibrosis (CF) is characterized by a pronounced antibody response and microcolonies surrounded by numerous polymorphonuclear neutrophils (PMN). Poor prognosis is correlated with a high antibody response to P. aeruginosa antigens. An animal model of this infection was established in two strains of mice: C3H/HeN and BALB/c, generally known as Th1 and Th2 responders, respectively, which were challenged with alginate-embedded P. aeruginosa. Mortality was significantly lower in C3H/HeN compared to BALB/c mice (p < 0.025). P. aeruginosa was cleared more efficiently in C3H/HeN mice and significantly more C3H/HeN mice showed normal lung histopathology (p < 0.02), and we found significantly fewer microabscesses in C3H/HeN mice than in BALB/c mice (p < 0.005). In supernatants from P. aeruginosa antigen and concanavalin A-stimulated spleen cells from the two strains of mice, the interferon-(IFN-) gamma levels were higher, whereas IL-4 levels were lower in C3H/HeN mice than in BALB/c mice. The implications of these findings for CF patients with chronic P. aeruginosa lung infection are discussed.

Susceptibility of various species of animals and strains of mice to Gymnophalloides seoi infection and the effects of immunosuppression in C3H/HeN mice

Susceptibility to Gymnophalloides seoi infection was studied in 8 species of animals, including 7 strains of mice; the effects of immunosuppression on susceptibility were examined in C3H/HeN mice. One hundred metacercariae of G. seoi isolated from naturally infected oysters were orally administered to each animal. Worm recovery rate (WRR), worm dimensions, and the number of uterine eggs were obtained at day 3 and day 7 postinfection (PI). Average WRR from gerbils, hamsters, and cats at day 7 PI was 28.0%, 14.2%, and 10.9%, respectively, the former 2 figures of which were significantly higher than the rate of 0.0-4.0% from Sprague-Dawley rats, dogs, ducks, guinea pigs, and chicks. In the case of mice, average WRR at day 7 PI was 12.4% (KK strain), 11.8% (C3H/HeN), 9.6% (ICR), 6.4% (BALB/c), and 6.3% (ddY), respectively; the first 3 figures were significantly higher than the rates from other strains, which were 1.8% (A) and 0% (C57BL/6). At day 3 PI, WRR was much higher in all strains except C57BL/6. Worm maturation was the highest in C3H/HeN mice. Immunosuppression of C3H/HeN mice by injecting prednisolone for 7, 14, or 21 days prior to infection increased WRR at day 7 PI to 27.8%, 33.8%, or 67.5%, respectively. The results show that gerbils, hamsters, cats, and KK, C3H/HeN, ICR. BALB/c, and ddY mice are laboratory hosts that are fairly susceptible to G. seoi infection. In C3H/HeN mice, susceptibility was markedly enhanced by immunosuppression.

Monoclonal antibodies against Rous sarcoma virus integrase protein exert differential effects on integrase function in vitro

We have prepared and characterized several monoclonal antibodies (MAbs) against the Rous sarcoma virus integrase protein (IN) with the aim of employing these specific reagents as tools for biochemical and biophysical studies. The interaction of IN with the purified MAbs and their Fab fragment derivatives was demonstrated by Western blot (immunoblot), enzyme-linked immunosorbent assay, and size exclusion chromatography. A series of truncated IN proteins was used to determine regions in the protein important for recognition by the antibodies. The MAbs described here recognize epitopes that lie within the catalytic core region of IN (amino acids 50 to 207) and are likely to be conformational. A detailed functional analysis was carried out by investigating the effects of Fab fragments as well as of intact MAbs on the activities of IN in vitro. These studies revealed differential effects which fall into three categories. (i) One of the antibodies completely neutralized the processing as well as the joining activity and also reduced the DNA binding capacity as determined by a nitrocellulose filter binding assay. On the other hand, this MAb did not abolish the cleavage-ligation reaction on a disintegration substrate and the nonspecific cleavage of DNA by IN. The cleavage pattern generated by the IN-MAb complex on various DNA substrates closely resembled that produced by mutant IN proteins which show a deficiency in multimerization. Preincubation of IN with substrate protected the enzyme from inhibition by this antibody. (ii) Two other antibodies showed a general inhibition of all IN activities tested. (iii) In contrast, a fourth MAb stimulated the in vitro joining activity of IN. Size exclusion chromatography demonstrated that IN-Fab complexes from representatives of the three categories of MAbs exhibit different stoichiometric compositions that suggest possible explanations for their contrasting effects and may provide clues to the relationship between the structure and function of IN.

Onset of resistance to light Hymenolepis nana infection in mice of different strains

Rapidity in onset of resistance against Hymenolepis nana egg infection after a light primary infection was studied in low and high responder mice challenged at different time intervals. A very rapid acquisition of protection was observed in C57 and a delayed response in C3H mice. In both cases the effect of resistance on weight or worm number was related to the time of challenge infection, suggesting a "race against time" involving host response and parasite development, the outcome varying according to host genetic background.

Strain related variations in adenovirally mediated transgene expression from mouse hepatocytes in vivo: comparisons between immunocompetent and immunodeficient inbred strains

High efficiency gene transfer and gene expression in hepatocytes in vivo can be achieved using recombinant adenoviral vectors. However, the persistence of gene expression in different experimental animal models has been variable. To determine if similar differences could be observed in a single species, persistence of gene expression was studied in inbred strains of mice using a recombinant adenoviral vector that expresses human alpha 1-antitrypsin. Marked variability in the persistence of gene expression ranging from several weeks (C3H/HeJ and Balb/c) to more than 3 months [C57Bl/6, B10.A(2R) and B10.BR] was observed when this vector was transduced in different strains of inbred mice. This variability did not correlate with H-2 type. To evaluate the role of T and B cell immunity in the persistence of gene expression, congenic C3H-scid and Balb/c-scid mice were studied and found to have indefinite gene expression from transduced hepatocytes. These animals unlike their immunocompetent counter-parts were able to undergo secondary transduction of hepatocytes with a different recombinant adenoviral vector. These findings suggest that as yet unidentified genetic loci influence the persistence of adenovirus-mediated hepatic gene expression in vivo, and these effects are mediated at least in part, by the antigen specific immune system.

Developmentally regulated expression of a brain specific species of chondroitin sulfate proteoglycan, neurocan, identified with a monoclonal antibody IG2 in the rat cerebrum

The mammalian brain contains many species of proteoglycan. To identify each proteoglycan species, we have raised monoclonal antibodies against soluble chondroitin sulfate proteoglycans purified from 10-day-old rat brains. One monoclonal antibody, named monoclonal antibody 1G2, recognized two proteoglycan species with 220,000 and 150,000 mol. wt core glycoproteins (chondroitin sulfate proteoglycan-220 and chondroitin sulfate proteoglycan-150). Partial amino acid sequences of N-termini of their core proteins coincided with those of neurocan, a brain-unique chondroitin sulfate proteoglycan species, whose complete coding sequence was recently reported [Rauch et al. (1992) J. biol. Chem. 269, 19,536-19,547]. Western blots revealed that chondroitin sulfate proteoglycan-220 became detectable in the rat cerebrum on embryonic day 14, and that it disappeared from the brain around postnatal day 30. In contrast, a fairly large amount of chondroitin sulfate proteoglycan-150 remained in the mature brain. Immunohistochemical studies revealed that 1G2 antigen was first localized in the preplate zone, then both in the marginal zone and in the subplate of the rat cerebrum on embryonic day 16, prior to arrival of the first thalamic afferents at the cortex. On embryonic day 20, immunolabeling with monoclonal antibody 1G2 began to spread from the subplate into the developing cortical plate. On postnatal day 10, the neuropil of the cerebrum, except for the barrel field, was diffusely stained with the antibody, intensely in the hippocampus and superficial layers (I-III) of the cerebral cortex and weakly elsewhere. The barrel hollows were stained very weakly compared with the barrel walls at this stage. The immunoreactivity in the hippocampus and superficial cortical layers was weakened in the mature brain, so that no particular staining pattern, but weak and diffuse staining was observed in the adult rat cerebrum. The 1G2 antigen was immunohistochemically associated largely with glial fibrillary acidic protein-positive cells in primary cultures of the neonatal rat cerebrum. Both chondroitin sulfate proteoglycan-220 and chondroitin sulfate proteoglycan-150 were detected in the conditioned media not only of highly enriched cultures of fetal rat cortical neurons but also of pure cultures of mature astrocytes; more (12- to 20-fold) in the astrocyte conditioned media. Astrocytes, in addition to neurons, may be a cellular source of neurocan in brain at least under certain physiological conditions. The spaciotemporal expression pattern of 1G2 epitope-bearing proteoglycan, or neurocan, suggests that this proteoglycan species plays some roles at least in forming the elongation pathway for early cortical afferent fibers as well as the functional barrel structure in the somatosensory cortex.

Heterogeneity in the plasma levels of two acute-phase proteins in mice from inbred strains infected with Trypanosoma cruzi

We analyzed the variations observed in the plasma levels of both alpha-macroglobulins (AM) and serum amyloid P (SAP) in mice from three different inbred strains (C3H, Balb/C and C57black/6) acutely infected with Trypanosoma cruzi. SAP levels increased in C57black/6 and Balb/C mice but not C3H mice. AM levels increased in all C3H mice but not in C57black/6 mice and rose slightly in only 43% of the Balb/C mice. AM and SAP levels are differently modulated in patterns that may be strain-determined.

Association of vaccinia virus-expressed adenovirus E3-19K glycoprotein with class I MHC and its effects on virulence in a murine pneumonia model

The adenovirus type 2 (Ad2) early region 3 (E3) codes for a 19-kDa glycoprotein (gp19) that associates with the class I major histocompatibility (MHC) heavy chain in the endoplasmic reticulum (ER) and prevents the transport of class I MHC protein products to the cell surface. It has been shown previously in tissue culture that this reduction in class I MHC expression allows infected cells to escape detection by class I MHC restricted CD8+ cytotoxic T-lymphocytes (CTL). We now report the results of studies on the effects of Ad2/gp19 expression on virulence in vivo. Since we wanted to isolate the effect of Ad2/gp19 from the effects of other Ad E3 region gene products and human Ads do not replicate in the mouse, we cloned the Ad2/gp19 open reading frame (ORF) into the HindIII C region of WR vaccinia virus (VV). Two VV recombinants were constructed by inserting the Ad2/gp19 ORF in either an expressing (V-e19(+)) or a non-expressing (V-e19(-)) orientation under control of the VV P7.5 promoter. The V-e19(+)recombinant expressed Ad2/gp19 in infected tissue and could be co-precipitated with an antibody to the class I MHC antigen Kd. However, intracerebral or intranasal infections of BALB/c (H-2d), BALB.G (H-2g), or C3H (H-2k) mice showed that Ad2/gp19 expression by V-e19(+) had no significant effect either on viral lethality or on its ability to replicate in vivo when compared to V-e19(-). Furthermore, the nature of the CD8+ CTL response to a V-e19(+)-induced pneumonia in (H-2d) mice was unchanged by Ad2/gp19 expression. Modulating the CD8+ CTL response, by interfering with infected target presentation, may not be important in the control of VV replication or virulence in vivo when other aspects of the immune response to viral infection are not altered. However, the two VV recombinants V-e19(+) and V-e19(-) were both equally attenuated (10-fold) when compared to wild-type VV. This attenuation, which has been reported previously for an intracerebral infection, is believed to be caused by the disruption of a 37-kDa ORF in the VV HindIII C region. Interestingly, our studies showed that the attenuation is not accompanied by a reduction in viral titers in infected tissue.

Vaccination with the immediate-early protein ICP47 of herpes simplex virus-type 1 (HSV-1) induces virus-specific lymphoproliferation, but fails to protect against lethal challenge

Assessing the immunobiological function of the individual proteins of herpes simplex virus-type 1 (HSV-1) continues to be important in elucidating virus-host interactions and for the rational design of subunit vaccines. In this report, the non-structural, immediate-early protein ICP47 of HSV-1 was examined for its ability to induce virus-specific immune responses. The ICP47 protein, when expressed from a recombinant vaccinia virus or when produced by cell-free, in vitro translation, induced a vigorous HSV-1-specific lymphoproliferative response. However, other common parameters of immunity such as neutralizing antibody, delayed-type hypersensitivity, and class I major histocompatibility complex (MHC)-restricted cytotoxic T lymphocytes (CTL) were not induced by ICP47. Moreover, mice immunized with vaccinia-expressed ICP47 were unable to survive lethal challenge with virulent HSV, indicating that in spite of its ability to induce significant HSV-1-specific lymphoproliferation, ICP47 appears unable to afford protective immunity in vivo. Possible reasons for this failure and the implications of these results in terms of vaccine design are discussed.

DNFB contact sensitivity (CS) in BALB/c and C3H/He mice: requirement for early-occurring, early-acting, antigen-specific, CS-initiating cells with an unusual phenotype (Thy-1+, CD5+, CD3-, CD4-, CD8-, sIg-, B220+, MHC class II-, CD23+, IL-2R-, IL-3R+, Mel-14-, Pgp-1+, J11d+, MAC-1+, LFA-1+, and Fc gamma RII+)

Immunization of mice for contact sensitivity induces two different antigen-specific Thy-1+ cell activities that are required to act in sequence for elicitation of contact sensitivity. In this study, 2,4-dinitro-1-fluorobenzene contact sensitivity responses in BALB/c and C3H/He mice demonstrated the importance of early-acting and antigen-specific contact sensitivity-initiating cells to recruit the classical, late-acting contact sensitivity effector T cells. Employing in vitro treatment of sensitized cells with monoclonal antibodies to cell surface determinants and then incubation in complement, prior to adoptive cell transfer, the contact sensitivity-initiating cells were shown to have a surface phenotype that is quite unusual for antigen-specific cells [Thy-1+, CD5+, CD3-, CD4-, CD8-, sIg-, B220+, major histocompatibility complex class II-, CD23+, IL-2R-, IL-3R+, Mel-14-, CD44+ (Pgp-1+), J11d+ (HSA+), MAC-1+, LFA-1+, and Fc gamma IIR+], and is quite different from the late-acting, contact sensitivity-effector T cells (Thy-1+, CD5+, CD3+, CD4+, CD8-, sIg-, B220-, major histocompatibility complex class II-, CD23-, IL-2R+, IL-3R-, and CD44- (Pgp-1-), J11d-(HSA-), MAC-1-, LFA-1+, Fc gamma IIR-). Contact sensitivity initiation was required for elicitation of late 24-h 2,4-dinitro-1-fluorobenzene contact sensitivity responses, in both BALB/c and C3H/He mice. Moreover, relatively high doses of some monoclonal antibodies [anti-B220 (CD45RA) and anti-CD23 (IgE Fc epsilon II receptor)] were necessary to completely eliminate all contact sensitivity-initiating cells that permitted expression of late contact sensitivity-effector T-cell activity. In contrast, high doses of monoclonal antibody specific for surface determinants of late-acting contact sensitivity effector T cells (anti-CD3 and anti-CD4), when used in high doses similar to anti-B220 and anti-CD23, had no effect on contact sensitivity-initiating cell activity. Our results indicate that two very different antigen-specific Thy-1+ cells are necessary to elicit 2,4-dinitro-1-fluorobenzene contact sensitivity in BALB/c and C3H/He mice.

Antigenicity study of the new cognition-enhancing agent nefiracetam

The potential antigenicity of the new cognition-enhancing agent nefiracetam (N-(2,6-dimethylphenyl)-2-(2-oxo-1-pyrrolidinyl)acetamide, DM-9384, CAS 77191-36-7) was investigated by tests for passive cutaneous anaphylaxis (PCA), systemic anaphylaxis (SA) and skin reaction in mice and guinea pigs. Mice were sensitized with nefiracetam (10-100 micrograms/animal) or nefiracetam-egg albumin (OA) mixture (10 micrograms/animal). No IgE antibodies to nefiracetam were detected in plasmas obtained from nefiracetam and nefiracetam-OA sensitized mice, indicating that nefiracetam has no immunogenicity or antigenicity eliciting potential. Guinea pigs were sensitized with nefiracetam (20-100 or 20 mg/kg) or nefiracetam-OA (2 mg/kg). No antibodies to nefiracetam were detected in the sera obtained from sensitized guinea pigs by PCA. Neither SA nor skin reaction was observed in the sensitized guinea pigs after the injection of challenge. These results suggest that nefiracetam possesses no antigenicity in mice and guinea pigs.

Biotinylated diaminopyridine: an approach to tagging oligosaccharides and exploring their biology

Fluorescent tagging of free oligosaccharides by reductive amination permits sensitive detection and fractionation of these molecules. To expand the scope of this approach, we have synthesized a fluorescent reagent, 2-amino-(6-amidobiotinyl)pyridine. This reagent can tag oligosaccharides under nondegradative conditions with high efficiency. The resulting adducts show excellent fractionation by reverse-phase HPLC with sensitive detection in the low picomole range. When combined with sequential exoglycosidase digestion, stepwise sequencing of the sugar chains is possible. The biotinyl group can also be used to recover the sugar chain from reaction mixtures. The high-affinity interaction of the biotinyl group with multivalent avidin or streptavidin can be used to create the functional equivalent of neoglycoproteins carrying multiple copies of oligosaccharides of defined structure. These complexes allow the production of IgG antibodies directed against the oligosaccharide chain. They can also harness the power of (strept)avidin-biotin technology for the detection and isolation of oligosaccharide-specific receptors from native sources of recombinant libraries.

Antigenic protein specific for C3H strain mouse is a mitochondrial stress-70 protein

Cells derived from C3H strain mouse produce an antigenic protein (CSA) specific for this strain [Kusakabe, M., et al. (1988) J. Cell Biol. 107, 257-265]. To examine the molecular basis of CSA, cDNA cloning of the antigenic protein was carried out. The deduced amino acid sequence demonstrates that CSA is the same protein as peptide-binding protein 74 (PBP74), a novel member of the stress-70 family. However, comparison of the PBP74/CSA sequences between C3H/HeN and BALB/c strain mice reveals the substitution of two amino acids in the substrate-recognition domain of the stress-70 protein. Western blot analysis indicates that one out of these two residues, arginine at residue 578 in the PBP74/CSA sequence of C3H mouse, contributes to the immunogenicity of CSA. Moreover, the subcellular localization of PBP74/CSA in mitochondria is also demonstrated by immunohistochemical analysis using anti-CSA monoclonal antibody. Thus, it is interesting that a genetic marker sequence in mice is located on the gene encoding a mitochondrial stress-70 protein.

Generation of a monoclonal antibody specific for a new class of minor ganglioside antigens, GQ1b alpha and GT1a alpha: its binding to dorsal and lateral horn of human thoracic cord

We have established a monoclonal antibody, GGR41, specific for a new class of minor gangliosides, such as GQ1b alpha and GT1a alpha, by immunizing mice with a GQ1b-rich ganglioside fraction extracted from bovine brain. Each of those minor gangliosides has been reported to be one of the cholinergic-specific gangliosides (Chol-1). Careful examination of binding specificity of the antibody by both an enzyme-linked immunosorbent assay and immunostaining on thin-layer chromatograms showed that the antibody recognizes three sialyl residues separately attaching to the gangliotetraosyl backbone structure. Immunohistochemical analysis revealed that GGR41 immunostained lamina I and III of dorsal horn and lateral horn of human thoracic cord but motor neurons were not immunostained. Except for negative staining of motor neurons, this distribution is similar to the distribution pattern of staining as reported in rats and humans using a polyclonal antibody against Chol-1. Thus, the antibody obtained in this study should be a useful reagent to study the function of a unique new class of the minor gangliosides.

Antigenic heterogeneity of Qa-2 antigens in C57BL/6

The Qa-2 antigens are class I-like molecules encoded by genes mapped telomeric to the H-2D region on chromosome 17 in the mouse. A panel of 8 new monoclonal anti-Qa-2 antibodies derived from a C3H.KBR anti-C3H. SW immunization was studied. Immunoprecipitation of 125I-labeled C57BL/6 splenocyte antigens showed that all of these antibodies precipitated 40 kDa molecules which could be completely precleared by the monoclonal antibody 20-8-4, which had previously been shown to crossreact with Qa-2. One of the monoclonal antibodies (1-12-1), however, was found not to completely preclear Qa-2 antigens precipitable by the other 7 antibodies or by 20-8-4, suggesting the existence of at least two different species of Qa-2 molecules. Cell lines transfected with Q7 or Q9 genes were reactive with all 9 antibodies and the Qa-2 antigens expressed on surface membranes of these cells were completely precleared by both 20-8-4 and 1-12-1. Therefore, the observed heterogeneity of these molecules cannot be explained by an antigenic difference between the Q7 and Q9 gene products. 2D gel analyses showed identical pI spectra between Qa-2 molecules precipitated with 20-8-4 and 1-12-1. In addition, all of the monoclonal antibodies reacted with labeled antigen preparations following treatment with Endo F or neuraminidase, indicating that carbohydrate moieties are probably not responsible for the antigenic difference between the two species of Qa-2 antigen.

Protection of three strains of mice against lethal influenza in vivo by defective interfering virus

This report examines the protective effects of defective interfering (DI) WSN on three strains of mice (C3H/He-mg (H-2k), C57BL/6 (H-2b) and BALB/c (H-2d)) infected with various doses of A/WSN influenza virus. All three strains were protected in terms of morbidity and mortality, to varying extents, DI WSN protected optimally against a low but lethal dose of A/WSN in C3H/He-mg mice, but also protected this and other strains against very high doses of A/WSN. Intermediate sized inocula gave little, if any, protection. In all cases protection required an active DI genome since inactivation with beta-propiolactone abrogated any sparing effect. Consolidation of the lungs was reduced by treatment with active DI virus, but at some doses of inoculum there was reduction in lung pathology without reduction of mortality. Treatment of infected mice with DI virus did not reduce the lung virus titre, but in C3H/He-mg mice resulted in recovery of infectious virus from other tissues, notably the heart, where it was not normally found. No infectivity was recovered from brain, liver or serum. Haemagglutination-inhibiting (HI) antibody could not be detected in the lungs of any of the infected mice co-inoculated with the control BPL-inactivated DI WSN but was present in considerable amounts in all three strains when these were co-inoculated with DI virus. These and previous data (Morgan and Dimmock, 1992) suggested that influenza virus was immunosuppressive and that active DI virus abrogated these suppressive effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Radioresistance of intermediate TCR cells and their localization in the body of mice revealed by irradiation

Extrathymic generation of T cells in the liver and in the intestine was recently demonstrated. We investigated herein whether such T cells, especially those in the liver, are present in other organs of mice. This investigation is possible employing our recently introduced method with which even a minor proportion of extrathymic, intermediate TCR cells in organs other than the liver can be identified. Intermediate TCR cells expressed higher levels of IL-2R beta and LFA-1 than bright TCR cells (i.e., T cells of thymic origin) as revealed by two-color staining. Although intermediate TCR cells were present at a small proportion in the spleen and thymus, they predominated in these organs after irradiation (9 Gy) and bone marrow reconstitution, or after low dose irradiation (6 Gy). This was due to that intermediate TCR cells were relatively radioresistant, whereas bright TCR cells were radiosensitive. Microscopic observation and immunochemical staining showed that intermediate TCR cells in the spleen localized in the red pulp and those in the thymus localized in the medulla. These intermediate TCR cells displayed a large light scatter, similar to such cells in the liver. The present results suggest that intermediate TCR cells may proliferate at multiple sites in the body.

Elevated production of interleukin 6 by hepatic MNC correlates with ICAM-1 expression on the hepatic sinusoidal endothelial cells in autoimmune MRL/lpr mice

MRL/lpr mice, which are a model of SLE and rheumatoid arthritis in humans, develop profound lymphadenopathy resulting from the accumulation of CD3+ 4-8- double-negative (DN) alpha beta T cells in peripheral lymphoid tissues. We previously indicated that these DN alpha beta T cells preferentially proliferate in the liver and migrate to the periphery. In this study, we analyzed whether any kind of cytokine was produced by hepatic mononuclear cells (MNC) in MRL/lpr mice. The evidence obtained indicates that interleukin 6 (IL-6) was vigorously produced by hepatic MNC in diseased MRL/lpr mice under unstimulated conditions. MNC in the spleen of these mice produced small amounts of IL-6, while those in the lymph nodes did not produce any appreciable amounts of IL-6. These activities of hepatic MNC in diseased MRL/lpr mice were almost completely neutralized by anti-mouse IL-6 monoclonal antibody (mAb). On the other hand, immunohistochemical staining of light- and electron-microscopic analyses revealed that the intracellular cell adhesion molecule 1 (ICAM-1) was expressed on the hepatic sinusoidal endothelial cells of diseased MRL/lpr mice. Moreover, ICAM-1 was newly induced in the hepatic sinusoids of control C3H/He mice by an intravenous injection of 50 units of recombinant mouse IL-6. These data suggest that ICAM-1 expressed on the hepatic sinusoidal endothelial cells in MRL/lpr mice is induced by IL-6, which is produced by hepatic MNC, and that such ICAM-1 may be responsible for the saturation of inflammatory cells and the proliferation of lymphocytes in the liver of MRL/lpr mice.

Locus controlling Bordetella pertussis-induced histamine sensitization (Bphs), an autoimmune disease-susceptibility gene, maps distal to T-cell receptor beta-chain gene on mouse chromosome 6

Pertussis toxin (PTX) is the primary component responsible for eliciting the majority of biological activities associated with Bordetella pertussis, including the induction of several tissue-adjuvant models of organ-specific autoimmune disease. PTX, when administered in vivo, enhances vascular permeability, which is made manifest by a concomitant increase in sensitivity to a variety of agents and treatments affecting the vascular bed. One such agent is histamine, and the response to PTX, as measured by hypersensitivity following vasoactive amine challenge, is genetically controlled by the Bphs locus. Susceptibility to the induction of both experimental allergic encephalomyelitis (EAE) and experimental allergic orchitis (EAO) in mice is associated with, and in the latter case linked to, a susceptible allele at this locus. We report here the mapping of the Bphs locus to mouse chromosome 6, telomeric of Tcrb and centromeric of Prp (D6Nds8). This region also contains a number of loci of immunologic relevance including Igk, Ly-2, Ly-3, Il-5r, Ly-35, Ly-4, and Tnfr-2.

Animal models of systemic vasculitis

Necrotizing leucocytoclastic vasculitis is the histopathological hallmark of the small vessel systemic vasculitides (SV), a group of human diseases commonly associated with anti-neutrophil cytoplasm autoantibodies (ANCA). Necrotizing vasculitis is seen in a number of experimental systems, but none of these provide an ideal animal model for human SV. Vasculitis occurs in serum sickness reactions; in murine models of systemic lupus erythematosus; in association with infection, particularly chronic viral infections; and after treatment with certain drugs or inflammatory mediators. 'Spontaneous' vasculitis has been reported in specific mouse strains, especially with ageing, and in some larger species. The size of vessel involved and the type of inflammatory cells predominating are variable in these experimental situations, and none of these models feature antibodies analogous to ANCA. We have recently reported that Brown Norway rats treated with mercuric chloride (HgCl2) develop necrotizing leucocytoclastic vasculitis, especially in the gut, and also develop antibodies to myeloperoxidase (MPO) which recognize similar determinants on MPO to those bound by a subset of ANCA. Transfer of serum from HgCl2-treated rats to naive animals does not induce tissue injury. Preliminary experiments using pooled immunoglobulin or an anti-CD4 monoclonal antibody did not show useful therapeutic benefit from these treatments. HgCl2-induced vasculitis has weaknesses as an animal model of human SV, but is the only experimental model in which anti-MPO autoantibodies have so far been demonstrated, and therefore may be of particular relevance to ANCA-associated SV.

Lipopolysaccharide nonresponder cells: the C3H/HeJ defect

Since its initial discovery as endotoxin resistant, the C3H/HeJ mouse has been extensively studied and used as a comparative model to help reveal the mechanism under genetic control which governs host responses to endotoxin. Most of the research has focused on the B lymphocyte and macrophage of this strain which fail to be activated by LPS. Recently, specific LPS binding proteins have been isolated on lymphocytes and other cells; however a receptor which transduces an activation signal has not been isolated as yet from responder cells which is missing or altered on C3H/HeJ nonresponder cells. Investigations into the signal transduction pathways used by C3H/HeJ B cells when they are activated by a protein mitogen have been found to be similar to those used by LPS responder cells when activated by LPS. Protein kinase C and tyrosine kinase, which phosphorylate signal proteins in cells have been found to be operative in C3H/HeJ and C3H/OuJ B cells. In both cases, DNA synthesis is shut off by either PKC or PTK blockade; however, PTK inhibition will also block activation of PKC stimulated DNA synthesis, indicating tyrosine kinase initiated phosphorylation may regulate the PKC signal pathway. Further analysis of the proteins that are phosphorylated in LPS responder and LPS nonresponder B cells is needed before conclusions can be drawn as to whether the defect in C3H/HeJ cells resides in the signal pathway leading to gene activation and proliferation. Nevertheless, the notion of a missing or defective signal receptor still remains as a working hypothesis to explain C3H/HeJ cell hyporesponsiveness to LPS. Isolation of the Lpsn gene and its product will provide the evidence needed for a clearer understanding of how LPS reacts with cells.

Gene structure, chromosomal localization, and protein sequence of mouse CD53 (Cd53): evidence that the transmembrane 4 superfamily arose by gene duplication

CD53 is a pan-leukocyte surface glycoprotein which spans the plasma membrane four times and is a member of the transmembrane 4 superfamily (TM4SF). The protein sequence and gene structure of mouse CD53 (Cd53) were determined by isolation of both genomic and cDNA clones. CD53 is highly conserved in evolution, as mouse Cd53 was 91% identical to rat CD53 and 82% identical to human CD53. The mouse Cd53 gene spanned approximately 9.0 kb of DNA and encoded the 219 amino acid residues of CD53 over seven exons. The Cd53 gene produced a 1.8 kb transcript which was dramatically upregulated after cell activation. The mouse Cd53 gene was mapped to chromosome 3, whereas the locus of another TM4SF member, CD37 (Cd37), was mapped to mouse chromosome 7. Three lines of evidence suggest that the TM4SF arose divergently from an ancestral gene. First, the gene structure of CD53 was strikingly similar to two other members of the TM4SF, CD63 and TAPA-1; second, Cd37 mapped to the same chromosome as Tapa-1; and, third, Cd37 mapped to a segment of chromosome 7 that contains a number of genes that are structurally or functionally related to genes closely linked to Cd53 on chromosome 3.

Isolation and characterization of monoclonal antibodies to recombinant bovine interleukin-1 beta

We describe the preparation of monoclonal antibodies (Mabs) directed against recombinant bovine interleukin-1 beta (rBoIL-1 beta). These anti-IL-1 beta Mabs were designated SA10, SA12, SA13, SA15, and SA22, and were characterized on the basis of their epitope specificity and cross-reactivity with homologous and heterologous cytokines in enzyme-linked immunosorbent assays and immunoblot analyses. Additionally, the ability of these Mabs to neutralize IL-1 beta was tested in thymocyte costimulation assays. The ELISA titers of all Mabs ranged from 9.4 x 10(6) to 1 x 10(7). Data indicate that Mabs SA10, SA12, SA15, and SA22 neutralized both bovine macrophage-derived IL-1 (1:4) and rBoIL-1 beta (1 ng ml-1). All the Mabs against rBoIL-1 beta (SA10, SA12, SA13, SA15, SA22) were specific and did not cross-react with other cytokines tested, except recombinant human IL-1 beta (rHuIL-1 beta). This finding suggests that these Mabs recognize epitopes common to human and bovine IL-1 molecules. Competition experiments suggested that Mab SA22 recognized a different epitope and Mabs SA10, SA12, SA13, and SA15 recognized the same epitope on the rBoIL-1 beta molecule. These observations suggest that these Mabs could be useful reagents for developing immunoassays to measure bovine IL-1 beta from biological fluids and to study the immunoregulatory role of IL-1 in the bovine immune system.

Selection of intestinal intraepithelial lymphocyte T cell receptors: evidence for a dynamic tissue-specific process

An extensive comparison of TCR alpha beta V-region usage by CD8 beta-CD4+CD8+ intraepithelial lymphocytes (IEL), CD4-CD8+ IEL, and lymph node (LN) T cell subsets in three minor lymphocyte stimulating (Mls)-disparate, MHC-identical mouse strains revealed novel TCR selection patterns. In cases where forbidden V regions were expressed by CD8 beta- CD4-CD8+ IEL, the same TCRs were deleted from CD8 beta- CD4+CD8+ IEL, indicating that lack of CD8 beta expression was not solely responsible for forbidden V-region expression. These results also suggested that CD4 may be involved in negative selection of CD4+CD8+ IEL TCRs. In C57BR/cdJ (Mls-1b2b) mice, a major increase in V beta 3+CD4+CD8+ IEL but not in other IEL or LN subsets was noted suggesting a subset-specific expansion of V beta 3+ cells. Negative selection of V beta 14+ cells in only the CD4+CD8+ IEL subset further supported the existence of intestine-specific TCR selection processes. Analysis of V-region expression of CD8 beta + and CD8 beta-CD4-CD8+ IEL subsets revealed that forbidden V-region expression was not strictly confined to the CD8 beta- subset in all cases. Overall, the data point to a dynamic, gut-specific TCR selection process that may be antigen driven.

Post-thymectomy organ-specific autoimmunity: enhancement by cyclosporine A and inhibition by IL-2

It has previously been shown that the administration of cyclosporine A to newborn mice results in the development of autoimmunity later in life. It has been proposed that the neonatal administration of cyclosporine A results in altered thymic selection or inhibition of the development of suppressor cells. In the present study, treatment of day 3 thymectomized C3H/HeN mice with cyclosporine A (20 mg/kg/day) for 9 d post surgery increased the prevalence of antigastric autoantibodies. In contrast, the administration of IL-2 (300-600 Units/g/day) for 7 days after thymectomy inhibited the development of antigastric antibodies. We hypothesize that CsA may act by causing transient lymphokine abnormalities in the extrathymic environment during the first few weeks of life which lead to the development of antigastric antibodies. In contrast to the inhibition of development of antigastric antibodies, the administration of a similar course of IL-2 produced only a transient suppression of diabetes in NOD mice. These results and other data suggest that diabetes in NOD mice is probably due to a different immunologic defect.

Efficacy of the herpes simplex virus types 1 and 2 mutant viruses to confer protection against zosteriform spread in mice

Two mutant viruses, HSV-2 XD192 and HSV-1 1716, failed to generate zosteriform lesions when injected in high dose into BALB/c and C3H mice. Mice exposed to mutant viruses were solidly immune to challenge by wild-type homologous or heterologous virus. However, at lower immunizing doses protection was evident against lethality, but not skin lesions, especially in the case of mutant XD192. Protection could be conferred with lymphoid cells from mutant virus immune mice and again, protection against lethality was more frequent than prevention of skin lesions. On the basis of cell fractionation studies, protection against lethality was assumed to be principally the function of CD8+ T lymphocytes. The implications of the results in terms of vaccine development were briefly discussed.

Two different mechanisms of immune-complex trapping in the mouse spleen during immune responses

The capacity of immune-complex (IC) trapping was examined using purified horse radish peroxidase (HRP)-anti-HRP (PAP) on frozen sections of mouse spleen in vitro. We investigated the trapping mechanisms by applying the IC with or without fresh mouse serum added on the spleen sections of naive as well as immunized mice. When the PAP was applied alone, it mainly located on the macrophages in red pulp. In the splenic white pulp of immunized mice, PAP was trapped on follicular dendritic cells (FDC) in a small area of the germinal center whereas it scarcely bound to the splenic white pulp of non-immunized mice. An antibody against mouse Fc receptor (2.4G2) blocked the trapping but antibodies against mouse complement receptor (8C12, Mac-1 and 7G6) did not. When the PAP was applied mixed with fresh mouse serum, it bound on FDC in the primary follicles in the spleen of non-immunized mice. The density and area of IC trapping increased in the spleen of immunized mice. IC trapping in the presence of fresh mouse serum was blocked by the antibodies 8C12 and 7G6 but not by 2.4G2 or Mac-1.

The effect of cyclophosphamide treatment on lymphocyte subsets in the nonobese diabetic mouse: a comparison of various lymphoid organs

The nonobese diabetic (NOD) mouse is a model for human Type 1 diabetes mellitus. Pancreatic beta-cell destruction in NOD mice is mediated by an autoimmune process which can be accelerated by cyclophosphamide (CP). We studied the phenotype of lymphocytes from central, peripheral and regional lymphoid tissues in prediabetic NOD and C3H mice before and after a single large dose of CP. All lymphoid organs showed a greatly diminished cell number and most alterations appeared early after CP and were transient, but an aggressive insulitis was not seen in NOD mice until 14 d after injection. The pancreatic islets in C3H mice remained intact and were not infiltrated. NOD female mice, which are most prone to spontaneous and CP-induced diabetes, exhibited the most unusual lymphoid kinetics after treatment with CP. Their thymus and spleen showed the least relative drop in total cell number and the most rapid rate of recovery. The thymus of these mice was also found to have an increased proportion of CD3+ thymocytes while CD4/CD8 double positive thymocytes decreased 7 d after CP. At 14 d after CP the number of IL-2R+ thymocytes had surpassed that of normal levels. The most dramatic observation was the rapid recovery and overshoot in the number of pancreatic lymph node cells of female NOD mice which coincided with aggressive insulitis.

Genetic studies of flavivirus resistance in inbred strains derived from wild mice: evidence for a new resistance allele at the flavivirus resistance locus (Flv)

Studies of genetic resistance to flavivirus infection in laboratory mice have led to the development of a single model in which resistance is conferred by an autosomal dominant gene designated Flvr. Because of evidence suggesting that wild mice carry virus resistance genes which are not present in laboratory mice, we compared flavivirus resistance in the inbred strains CASA/Rk, CAST/Ei, and MOLD/Rk, which are derived directly from wild mice, and the congenic strains C3H/RV (Flvr/Flvr) and C3H/HeJ (Flvs/Flvs). Resistance to the Murray Valley encephalitis virus strain OR2 and the 17D vaccine strain of yellow fever virus was assessed by determining the lethality of intracerebral infection and by measuring virus replication in the brain. The resistance of the CASA/Rk and CAST/Ei strains resembled the resistance of C3H/RV mice, whereas the resistance of the MOLD/Rk strain was intermediate between those of C3H/RV and C3H/HeJ mice. Genetic analyses showed that resistance in both the CASA/Rk and MOLD/Rk strains is conferred by single autosomal dominant alleles at the Flv locus. Our data indicate that flavivirus resistance in the CASA/Rk strain is due to a gene which is similar or identical to Flvr, whereas resistance in the MOLD/Rk strain is due to a previously undescribed gene which we designate Flvmr to indicate minor resistance to flavivirus infection. Since genetic resistance to flaviviruses is rare in laboratory mice, the CASA/Rk and MOLD/Rk strains will be valuable for further investigation of this phenomenon.

The monoclonal antibody TAL16.1 recognizes the aspartic acid residue at position 70 in DRB gene products

A polymorphic monoclonal antibody (TAL16.1), raised against a mouse L-cell transfectant expressing the human DRB5*0101 gene from the HLA-DR15(2) Dw2 DR51 haplotype was shown to have a complex pattern of reactivity to DRB gene products. The antibody bound to a transfectant expressing the DRB5*0101 allele against which it was produced but not to a transfectant expressing the DRB1*1501 allele. These alleles of the DRB1 and DRB5 genes are usually coexpressed on DR15(2) Dw2 DR51 cells. A comparison of the HLA-DRB amino acid sequences of reactive and non-reactive cells identified an aspartic acid residue at position 70, conserved in all antibody-positive cells and absent in antibody-negative cells, which was postulated as being responsible for conferring the specificity of the antibody. The aspartic acid residue at position 70 is present in DRB5*0101 and DRB5*0102 alleles but absent in DRB5*0201 and DRB5*0202 alleles, allowing the antibody to distinguish between these splits of the DR51 serological specificity. TAL16.1 also binds to the product of the DRB1*0103 allele and discriminates between cells with a DR103 specificity and the other DR1 subtypes, DRB1*0101 and DRB1*0102. In this report the value of transfectants as immunogens for use in the production of monoclonal antibodies of predetermined specificity and as tools for the fine mapping of antibody specificity is discussed.

Flow microfluorometric analysis of murine spermatozoa fails to detect H-2 antigens

The presence of class 1 and class 2 histocompatibility antigens on murine sperm was investigated by flow microfluorometry. Monoclonal anti-H-2Kk (class 1), anti-Iak (specificity 2, class 2) and allo-anti-Iak (class 2) antisera were used in direct or indirect fluorescence labelling experiments to probe the expression of class 1 and class 2 antigens on epididymal mouse spermatozoa. Sperm-specific antibodies were generated by intraperitoneal immunization of both male and female C3H/HeN mice with syngeneic spermatozoa. Sperm-specific antigens were detected in 68-85% of syngeneic mouse sperm and 65-90% of allogeneic mouse sperm examined. Conversely, these antibodies did not stain syngeneic or allogeneic lymphocytes above the background of the negative control. Mouse sperm samples failed to exhibit specific fluorescence above the background of negative control values with antibodies against either class 1 or class 2 MHC antigens. We have established the sensitive, objective and economical assay of sperm membrane antigens with fluorochrome-labelled antibodies by flow microfluorometry. By use of this sensitive and objective technique we have not detected MHC antigens on murine sperm. We conclude that these MHC antigens are not expressed on sperm at a level to be practically detectable.

Cytokine production by murine cells activated by erythrogenic toxin type A superantigen of Streptococcus pyogenes

The mode of pathogenic action of the Steptococcus pyogenes superantigen erythrogenic toxin type A (ETA) in causing toxic shock-like syndrome in humans is thought to be mediated by massive release of cytokines by patients immune cells. The cytokine-inducing capacity of ETA as an extracellular protein was compared with that of lipopolysaccharide (LPS), a component of cell wall of gram-negative bacteria. Peritoneal macrophages and splenocytes of BALB/c and C3H/HeJ mice were stimulated by ETA and LPS. Tumor necrosis factor (TNF), interleukin 3 (IL-3) and interleukin 6 (IL-6) activities in the supernatants of stimulated cells were evaluated. In contrast to LPS, ETA induced only low amounts of IL-6 and no detectable TNF activities in peritoneal macrophage supernatants. ETA-triggered BALB/c and C3H/HeJ splenocytes produced great amounts of IL-6. ETA triggered the production of IL-3 by both mice strains splenocytes in a dose dependent manner. The amounts of IL-3 in supernatants were comparable to those induced by concanavalin A. The simultaneous presence of ETA and LPS in macrophage and splenocyte cultures induced a slight enhancement above an additive value after 72-96 h. Challenge of BALB/c mice with ETA 6 h before the harvest of peritoneal macrophages led to an enhanced production of IL-6 upon stimulation with ETA as well as with LPS. Splenocytes of nude BALB/c mice did not produce IL-6 upon stimulation with ETA, whereas LPS-induced IL-6 production was similar in these mice and in their littermates. The pathogenic effect of ETA on host's immune cells could most likely be explained as a consequence of T cell activation. The results confirm also that LPS- and ETA-induced shock is mediated by different cell types.

New polymorphic HLA-DR epitopes recognized by three monoclonal antibodies produced against DR103 transfected L cells

Production of monoclonal antibodies directed against polymorphic epitopes of HLA class II molecules using whole human cells as immunogen has often proved ineffective, because most of the antibodies produced are directed against non-MHC human cell surface molecules. One approach to overcome this problem is the use of transfected mouse L cells expressing a single HLA class II allele as immunogen. By immunizing C3H mice with DR103-transfected L cells, we obtained 3 mAb, OHA TM901, OHA TM902, and OHA TM903, that recognize different polymorphic epitopes of the HLA-DR molecule. The molecular specificities of the 3 mAb were determined on a large panel of B-lymphoblastoid cell lines (B-LCL), peripheral blood cells and HLA class II transfectants from the XIth International Histocompatibility Workshop. Interestingly, the 3 polymorphic mAb detect new HLA-DR epitopes shared by several specificities: OHA TM901 reacts with DR1 (DR101, DR103), DR9 (DR901) and DR10 (DR1001) molecules; OHA TM902 recognizes the same molecules but also DR8 (DR801, 802, 803); OHA TM903 reacts with all DR types except DR3 (DR301, 302), DR7 (DR701, 702) and DR52. Surprisingly, OHA TM901 reacts with DR9 transfectants and B-LCL but not with DR9 peripheral blood lymphocytes. Biochemical analyses indicate that the 3 mAb immunoprecipitate HLA-DR products and react in western blots with DR alpha/beta-dimer but not with free alpha- or beta-chains. This study shows that transfected L cells are very useful tools for the production and the fine characterization of mAb recognizing polymorphic epitopes of HLA class II molecules.

Production and characterization of murine monoclonal antibodies recognizing HLA-DQ polymorphisms obtained by immunizing mice with transfected L cells

Two polymorphic anti-HLA-DQB1 mAbs, TM 902 and TM 903, have been produced by immunizing F1 mice (Balb/C x C3H) with HLA-DQ-transfected mouse L cells. Cytotoxic analysis on a panel of HLA-typed cell lines has shown that TM 902 reacts with all the DQB1* alleles except DQB1*0501, *0502, and *0503, and DQB1*0601, *0602, *0603, and *0604, whereas TM 903 reacts with the DQB1*0501, *0502, and *0503, DQB1*0601, *0602, *0603, and *0604, and DQB1*0401 and *0402 alleles. The same reactivity pattern has been confirmed by cytofluorimetric analysis. Indirect immunofluorescence with various class-II-transfected cell lines showed no binding of both mAbs to the DR or DP products, suggesting their reactivity to the DQ products. The use of transfectants expressing HLA-DR/DQ heterodimers demonstrates that TM902 and TM903 mAbs are both specific for the DQ-beta chain. Comparison of the amino acid sequences of the DQ-beta chain suggests the involvement of residues 84-90 (QLELRTT) in the formation of TM902 epitope and of residues 54-55 (GR) in the formation of TM903 epitope.

Immunosuppression induced by hepatic portal venous immunization spares reactivity in IL-4 producing T lymphocytes

Immunization of naive or specifically primed C3H/HEJ with irradiated B10.BR spleen cells via the hepatic portal vein leads to an antigen specific decrease in the proliferative and cytotoxic response to B10.BR antigen assayed in vitro (and to increased graft survival of B10.BR grafts in vivo). This effect seems to be mediated in the main by a decrease in IL-2 production from CD4+ T lymphocytes of mice given antigen by the portal route, which is in turn caused by a decreased precursor frequency of IL-2-producing cells. No clear decrease in IL-4 production was seen. Hepatic APC isolated from mice receiving antigen via the portal vein were unable to induce IL-2 production from a C3H/HEJ anti-B10.BR cell line in vitro, in contrast to splenic APC derived from the same mice. Even when antigen was given by conventional (systemic) intravenous routes (in this case via the lateral tail vein) hepatic APC isolated from those mice were unable to stimulate IL-2 production from this cell line. Furthermore, 24 h exposure of a cell line to antigen pulsed hepatic APC left those cells refractory to a subsequent restimulation with antigen presented by splenic APC. Spleen lymphoid cells from primed mice challenged in vivo with B10.BR liver cells (i.v.) were similarly unable to produce IL-2 on rechallenge in vitro with irradiated B10.BR spleen cells, though no defect was seen if in vivo challenge was with B10.BR spleen cells. These data imply that presentation of multiple minor cell surface antigens by hepatic APC leads to specific anergization of IL-2 producing T cells, in a fashion which seems to be distinct from that previously reported as due to 'veto-like' activity.

Generation of murine monoclonal antibodies specific for N-glycolylneuraminic acid-containing gangliosides

We generated two murine monoclonal antibodies (MAbs) specific for mono- and disialylgangliosides having N-glycolylneuraminic acid (NeuGc) as their sialic acid moiety, respectively, by immunizing C3H/HeN mice with these purified gangliosides adsorbed to Salmonella minnesota followed by fusion with mouse myeloma cells. By use of a wide variety of glycolipids, including NeuGc-containing gangliosides, the precise structures recognized by these two antibodies were elucidated through enzyme-linked immunosorbent assay and immunostaining on thin-layer chromatography. One MAb, GMR8, which was generated by immunizing the mice with purified GM3(NeuGc), reacted specifically with gangliosides having NeuGc alpha 2----3Gal- terminal structures, such as GM3(NeuGc), IV3NeuGc alpha-Gg4Cer, IV3NeuGc alpha-nLc4Cer, V3NeuGc alpha-Gb5Cer, and GD1a(NeuGc, NeuGc). None of the other gangliosides having internal NeuGc alpha2----3Gal- sequences, such as GM2(NeuGc) and GM1(NeuGc), nor corresponding gangliosides having NeuAc alpha 2----3Gal- sequences, nor neutral glycolipids were recognized. Thus, the epitope structures recognized by the MAb were found to be strictly NeuGc alpha 2----3Gal- terminal structures. In contrast, the other MAb, GMR3, which was generated by immunizing the mice with purified GD3(NeuGc-NeuGc-) adsorbed to the bacteria, reacted specifically with gangliosides having NeuGc alpha 2----8NeuGc alpha 2----3Gal- terminal sequences, such as GD3(NeuGc-NeuGc-), IV3NeuGc alpha 2-Gg4Cer, IV3NeuGc alpha 2-nLc4Cer, and V3NeuGc alpha 2-Gb5Cer, but did not react with corresponding gangliosides having NeuAc as their sialic acid moiety or with the neutral glycolipids tested. The epitope structures recognized by the MAb were suggested to be NeuGc alpha 2----8NeuGc alpha 2----3Gal- terminal structures. Using these MAbs, we determined the distribution of such gangliosides in the spleen, kidney, and liver of several mice strains. Novel gangliosides reactive with these MAbs were detected in these tissues.

V beta 17 T-cell deletion by endogenous mammary tumor virus in wild-type-derived mouse strain

The wild-type-derived mouse strain PWK possesses a beta-chain variable region V beta 17a2 allele, which is expressed on mature T cells as part of the T-cell receptor of most mice expressing I-E, whereas V beta 17 T cells are deleted in all I-E+ laboratory mice bearing a V beta 17a1 allele. However, (PWK x CBA/J)F1 progeny and the wild-type-derived mouse strain MAI, which possesses the V beta 17a2 allele, display deletion of V beta 17 T cells. Analysis of (PWK x CBA/J) x PWK and of (PWK x MAI) x PWK backcrosses demonstrates that endogenous mouse mammary tumor virus MTV-6 from CBA/J and a MTV from strain MAI control the clonal deletion of V beta 17a2 as well as V beta 3 T cells. Furthermore, among I-E- progeny of a (MAI x C57BL/6) x C57BL/6 backcross, we observed that mice inheriting MTV of MAI have a reduced level of V beta 17 T cells, suggesting that the clonal deletion of V beta 17a2 T cells can be mediated in the absence of the I-E molecule. The 3' long terminal repeat of MTV MAI was cloned and translation of the open reading frame was compared to those of MTV known to encode superantigens. Comparisons indicate that MTV MAI has significantly diverged from the other MTVs. However, MTV MAI and MTV-6 share a stretch of 11 identical amino acids at the C terminus, which is divergent in MTV reacting with other V beta s. This suggests that this region is involved in determining the specificity toward V beta s and has been selectively conserved through evolution of the Mus species.

Design and immunological properties of topographic immunogenic determinants of a protein antigen (LDH-C4) as vaccines

Antibodies elicited by immunization with short peptides containing antigenic determinants have been shown, in general, to bind with greatly reduced affinity to the corresponding region in the native proteins. Thus, contiguous linear peptides have not proven to be effective immunogens in generating high affinity neutralizing or protective antibodies and consequently appear to be poor prospects for vaccines. The molecular basis for such reduced reactivity is clear from the crystal structure determination of antibody Fabs bound to protein antigens, which showed the complementarity between interfaces to be lock-and-key-like and extending over a large area (750 A2) involving discontinuous segments of the polypeptide chain. Thus, small perturbations in the secondary and tertiary structure of the antigen have profound effects on the fit of the antigen and its corresponding antibody. Because short peptides are unlikely to assume any particular conformation in solution, the fit is likely to be poor. New strategies are therefore required to produce conformationally stable peptides that mimic the critical structural features of the protein antigenic site. Here we show that a putative topographic determinant of the testis-specific isozyme of lactate dehydrogenase C4 (LDH-C4), designed and synthesized to adopt a well defined alpha-helical secondary and tertiary structure (four-helix bundle motif) in aqueous solutions, is highly immunogenic in both rabbits and mice, inducing IgG antibodies that bind to native LDH-C4. This engineered conformational 40-residue peptide is considerably more effective in inducing antibodies, as compared with the corresponding linear peptide. The antibody response is obtained without coupling the peptide to a carrier protein, suggesting that the peptide contains a T-cell antigenic determinant. The strategy described here to produce a conformationally stable peptide that mimics the native structure may have general applications in vaccine design.

Conditioned stress responses by pregnant and/or lactating mice reduce immune responses of their offspring after weaning

C3H/HEJ mice repeatedly exposed to rotational stress (45 rpm for 30 min) show a decreased immune response after challenge with sheep erythrocytes (SRBC) or multiple minor histoincompatible skin grafts (B10.BR) in association with the cues present when initially exposed to the physical stress. This conditioned immunosuppression is associated with diminished antibody production and enhanced skin graft survival. When previously conditioned mice were mated with normal (nonconditioned) males and reexposed to conditioning cues during pregnancy (days 13, 16, and 19 of gestation), the offspring of these mice were also found to produce a decreased antibody response (and decreased skin graft rejection response) when tested at 7 weeks of age. This altered immune response in the offspring occurred in the absence of any deliberate direct manipulation of these mice. In a further study a reciprocal crossover design was used to investigate whether altered immunity in the offspring was dependent upon the treatment of the biological mother and/or the fostering mother. The most marked immunosuppression was seen in offspring born to, and fostered on, conditioned mothers reexposed to cues previously associated with physical stress. However, even the offspring of of normal C3H/HEJ matings developed a reduced immune response if they were fostered on conditioned mothers reexposed to stress-associated cues. These data imply that the developing immune system is regulated by factors in the colostrum/feto-placental unit which are modified by conditioning phenomena.

Enhancement of effector cell activities in mice bearing syngeneic plasmacytoma X5563 by a biological response modifier, PSK

We investigated the effect of PSK, a protein-bound polysaccharide obtained from Coriolus versicolor of basidiomycetes, on antitumor immunity in tumor-bearing mice. PSK prolonged significantly the life span of C3H/He mice bearing syngeneic plasmacytoma X5563 in a schedule- and dose-dependent manner. PSK was most effective when administered at 100 mg/kg every other day ten times starting from the day after tumor inoculation. The administration of PSK enhanced significantly the cytostatic activity of peritoneal exudate plastic-adherent cells and the cytolytic activity of spleen cells after in vitro incubation with mitomycin C-treated tumor cells. In addition, PSK restored the cytokine-producing capacity of spleen cells suppressed in tumor-bearing mice after in vitro incubation with mitogen. Sera from tumor-bearing mice suppressed the activity of such effector cells as well as the interleukin 2-producing capacity of spleen cells, but sera from PSK-treated tumor-bearing mice prevented this suppression. These results suggest that PSK enhances antitumor immunity by reducing immunosuppressive activity of serum from tumor-bearing mice.