Direct effect of cyclosporin A on CD8+ T lymphocytes in a primary mixed lymphocyte reaction

Cyclosporin A (CsA) blocks the development of cytotoxic T lymphocytes (CTL) in a primary mixed lymphocyte reaction (MLR) when added during the first few days of culture. We found that addition of recombinant IL-2 (rIL-2) or an IL-2-containing supernatant (2 degrees MLR SN) either alone or in combination was unable to reverse the suppression. Purified CD8+ responder cells were inhibited as effectively by CsA as unfractionated cells, suggesting that CsA has a direct, lymphokine-independent effect on CD8+ cells. The frequency of CTL precursors (CTLp) responding in a primary MLR was measured by limiting dilution in the presence and absence of CsA. Using either unfractionated cells or cell-sorter-purified CD8+ responder cells, no suppression was seen at very low cell numbers but increased markedly as the cell number per culture increased. These results imply that either a CD8+ regulatory/suppressor cell is being diluted out at low cell numbers, or that low cell-density culture conditions might override the inhibitory effects of CsA.

Epitope mapping and use of anti-idiotypic antibodies to the L6 monoclonal anticarcinoma antibody

Mouse monoclonal anti-idiotypic antibodies (anti-ids) were raised against L6, a murine IgG2a monoclonal antibody specific for a cell surface antigen expressed by many human carcinomas. Ten distinct anti-ids were generated. Eight anti-ids were shown to inhibit the binding of L6 to its target antigen and were characterized in detail. The heavy and light chain variable region gene segments of the monoclonal antibody L6 linked to human constant regions (chimeric L6) were expressed separately or together, to map the epitopes recognized by the anti-ids. Individual anti-ids were shown to recognize heavy chain, light chain, or combinatorial variable region determinants. Defining these specificities enabled us to select particular anti-ids for assays to monitor the pharmacokinetics of either murine or chimeric L6 antibodies in the circulation of human patients. A quantitative enzyme-linked immunosorbent assay developed with two anti-ids accurately detects less than 5 ng/ml. Anti-ids specific for light chain variable region-encoded determinants were capable of recognizing L6 antigen-binding fragments bound to the surface of human carcinoma cells. These anti-ids can be used to study the binding of chimeric L6 antibody at the surface of tumor cells in histological sections of tumor biopsies.

Differential immune responsiveness in mouse lines selectively bred for high and low sensitivity to ethanol

Natural killer cell activity was compared in the Long-Sleep and Short-Sleep mouse lines. These mice, initially selected for their sensitivities to a hypnotic dose of ethanol, are also differentially sensitive to other agents which act through the benzodiazepine/GABA receptor chloride ionophore complex. Natural killer cell activity was 40-59% lower in Short-Sleep when compared to Long-Sleep mice. Flow cytofluorometric analysis demonstrated that the number of Nk-1+ cells was also lower in the spleens of Short-Sleep than Long-Sleep mice. In addition, the incidence of 3-methylcholanthrene-induced tumors was significantly greater in Short-Sleep (85.7%) than in Long-Sleep (14.3%) mice. These results suggest that the Long-Sleep and Short-Sleep mouse lines may represent a unique model to assess the physiological role of the benzodiazepine/GABA receptor chloride ionophore complex in the neural modulation of immune function.

The optimisation of immunoglobulin secretion in vitro by mouse spleen cells and hybridoma cells

Optimal culture conditions and cell densities for antibody production by spleen cells from mice infected with Trypanosoma brucei, and by hybridoma cells, were assessed in vitro by a silver-immunogold (SIG) blot technique and an enzyme-linked immunosorbent assay (ELISA). The blot assay measured the proportion of secreting cells in the population and the ELISA measured the quantity of synthesised and secreted immunoglobulin (Ig) in cell lysates and in 3-h culture supernatants. Marked inhibition of Ig secretion occurred when cells were cultured in conditions of confluence. When cells were maintained in rotating cultures, no inhibition was seen. These cells maintained a steady rate of Ig synthesis and secretion over 3 h.

Splenic natural cytotoxic activity is enhanced during growth of a murine fibrosarcoma

We have shown previously that the natural killer (NK) cell activity of DBA/2J mice bearing M-1 fibrosarcomas is consistently depressed at the later stages of tumor growth. The apparent mechanisms of inhibition are suppressor cell activation and prostaglandin E (PGE) production by tumor and lymphoid cells. In contrast, we show here that the natural cytotoxic (NC) activity of cells from the spleen, blood, and lymph nodes of mice bearing M-1 tumors is enhanced when compared to that of age- and sex-matched control mice. This enhanced NC activity does not appear to be due to increased cytolytic activity of macrophages but, rather, to enhanced cytolytic activity of multiple populations of non-adherent cells including B and T cells. Correlated with this is the finding that the NC activity of normal spleen cells is not inhibited in vitro by either PGE1 or PGE2 at levels which are inhibitory to NK cells. NC activity, although independent of PGE, is in fact enhanced by PGE1 in a dose-related fashion. These data indicate that NK and NC cells are regulated differently by PGE and during tumor growth. Utilizing a Winn assay, we also demonstrate that a cloned cell line with NC activity is capable of slowing tumor growth in vivo and that this action is improved if mice are treated with indomethacin concomitantly.

Induction of experimental systemic lupus erythematosus in mice by immunization with a monoclonal anti-La autoantibody

Experimental systemic lupus erythematosus (SLE) in mice can be induced by immunization either with a human monoclonal anti-DNA antibody bearing the 16/6 idiotype (16/6 Id) or with a mouse monoclonal anti-idiotypic antibody specific for the 16/6 Id. In the present report we investigated the pathogenic role of a monoclonal anti-La autoantibody in the induction and mediation of experimental SLE in mice. The monoclonal anti-La antibody was derived from a mouse in which experimental SLE was induced by immunization with the monoclonal anti-16/6 Id antibody. Following immunization with the anti-La antibody the mice produced antibodies to double-stranded DNA, single-stranded DNA, Sm, SS-A/Ro, SS-B/La, and ribonucleoprotein. Furthermore, even though the anti-La antibody does not express nor react with the 16/6 Id, the immunized mice produced high titers of anti-16/6 Id antibodies as well as 16/6 Id bearing antibodies. Four months following immunization the mice exhibited significant proteinuria, and kidney sections revealed immune complex deposits on the basement membrane of the glomeruli. These results suggest that anti-La autoantibodies are involved in the induction and mediation of SLE in mice.

[The effect of anti-T sera on the natural killer activity of the splenocytes in C3HA mice at different times after the transplantation of hepatoma 22a cells]

Suspension of splenocytes of control C3HA mice and mice examined early after transplantation of mouse hepatoma 22a cells were fractionated by treatment with anti-T-sera (anti-thymocytes, antibrain and anti-suppressor-T-cells). This treatment leads to various changes in NK-activity due to elimination of different subpopulations of T-lymphocytes. This variability may be associated with the presence of two or more types of suppressor cells able to influence the NK-cells directly or by means of other immunocompetent cells.

Coxsackievirus B3 myocarditis in C3H/HeJ mice: description of an inbred model and the effect of exercise on virulence

The effect of forced exercise on the development of coxsackievirus B3 myocarditis in inbred C3H/HeJ mice was studied. Four groups of mice (30 per group) were formed: infected-exercised (Group I); infected-unexercised (Group II); uninfected-exercised (Group III); and uninfected-unexercised (Group IV). Infected mice were inoculated intraperitoneally with 1.0 x 10(2.1) TCID50 coxsackievirus B3. Exercised animals were swum daily for 60 minutes on days 1-9. Myocardial viral titers were acutely elevated on day 3 of infection and were augmented significantly by exercise on days 6 and 9. Exercise increased the overall mortality from 0-10% to 20-40%; significantly increased heart: body weight ratios on days 6, 9 and 13; and increased the extent of myocardial fiber necrosis. We have reproduced the acceleration of CB3 myocarditis by exercise in the inbred C3H model.

Resistance of mice to genital infection with Neisseria gonorrhoeae

Five strains of mice (C3H, CBA, BALB/c, TO and ICR) were inoculated intra-vaginally with Neisseria gonorrhoeae in an attempt to produce an animal model of gonorrhoea. Of a total of 68 mice inoculated, only three (4.4%) were culture-positive after 3 days. Histological examination of both the genital mucosa of inoculated animals, and the mucosa of genital tract organ cultures inoculated in vitro failed to show any evidence of gonococcal adherence or colonisation. Mice of these strains, therefore, appear resistant to gonococcal infection of the genital tract.

Relationship of route of infection to susceptibility and immune response of inbred mice to Y strain Trypanosoma cruzi

C3HeB/FeJ (C3H) mice infected ip with 10(6), 5 x 10(5), and 10(5) blood-form trypomastigotes (BFTs) of the Y strain of Trypanosoma cruzi were more resistant than C57B1/6 (B6) mice infected in the same manner. This pattern of susceptibility is opposite that reported for other stocks of this parasite. In a second experiment, C3H and B6 mice were infected ip or sc with 2 x 10(6), 10(6), 5 x 10(5), 10(5), or 10(3) Y strain BFTs. C3H mice infected ip with the 3 highest doses were again more resistant than the B6 mice, while mice infected ip with the 2 lowest doses were essentially equivalent in resistance. Thus, the difference in susceptibility was detectable, in terms of parasitemia levels and survival, primarily at the higher infection doses. For the groups infected sc, the pattern of susceptibility reversed. B6 mice infected with the 3 highest doses had lower parasitemia levels than the corresponding C3H mice, while C3H and B6 mice infected with 10(5) or 10(3) BFTs were similar in resistance. Blastogenic responses of lymphoid cells to phytohemagglutinin (PHA) and a soluble trypanosome extract (STE) were compared for C3H mice infected ip or sc to determine if the susceptibility to infection obtained with the 2 routes would be associated with differences in immune responses. Mesenteric lymph node cells (MLNCs) of mice infected ip were responsive to the STE early in infection, while superficial lymph node cells (SLNCs) of these mice were not. C3H mice infected sc had SLNCs which yielded strong responses to STE, while their MLNCs were relatively unresponsive. PHA stimulated responses by lymphoid cells from mice infected ip or sc were similar.(ABSTRACT TRUNCATED AT 250 WORDS)

Organization and structure of the Qa genes of the major histocompatibility complex of the C3H mouse: implications for Qa function and class I evolution

We have determined the structure and organization of the entire Qa family of class I genes from the major histocompatibility complex of the C3H mouse. Restriction maps of overlapping lambda and cosmid clones reveal that there are only five Qak genes: Q1k, Q2k, Q4k, Q10k and a Q5/9 hybrid, presumably generated by unequal homologous recombination. The resulting deletion of Q6-Q9 is consistent with the Qa-2null phenotype of this mouse strain. We have sequenced the Qak genes, and predict that each may encode a class I molecule with a structure comparable with that proposed for the transplantation antigens. Furthermore, these Qa products should be able to bind peptides and interact with appropriate T-cell receptors. Interestingly, in comparing Qak and H-2k sequences, we find limited evidence of interlocus gene conversion between Qa and H-2 loci, suggesting that the Qa genes are not likely to serve as a reservoir of genetic information for the generation of H-2 diversity within this haplotype.

Immunomodulatory activity of monophosphoryl lipid A in C3H/HeJ and C3H/HeSnJ mice

Treatment with nontoxic monophosphoryl lipid A (MPL) derived from a polysaccharide-deficient, heptoseless Re mutant of either Salmonella typhimurium or Salmonella minnesota R595 enhanced the immunoglobulin M (IgM) anti-type III pneumococcal polysaccharide (SSS-III) antibody response of C3H/HeSnJ mice. Such an adjuvant effect was not observed in lipopolysaccharide-nonresponder C3H/HeJ mice. Nevertheless, C3H/HeJ spleen cells produced a weak mitogenic response to both preparations of MPL in vitro, and C3H/HeJ mice showed a significant increase in serum IgM levels without an increase in numbers of splenic IgM-secreting plaque-forming cells after in vivo treatment with MPL. A significant increase in serum IgG3 levels was accompanied by a transient decrease in serum IgG1 levels in C3H/HeSnJ mice given MPL; such non-antigen-specific polyclonal effects were not observed in C3H/HeJ or in athymic nu/nu mice. Since the enhanced antibody response to SSS-III has been attributed to the inactivation of suppressor T cells by MPL and since suppressor-T-cell activity is demonstrable in both C3H/HeSnJ and C3H/HeJ mice, these findings imply that (i) the suppressor T cells of C3H/HeJ mice are refractory to inactivation by MPL and (ii) some of the polyclonal and mitogenic effects produced in C3H/HeJ mice are due to the direct action of MPL on B lymphocytes.

Particle size of airborne mouse crude and defined allergens

Laboratory animal allergy is a serious occupational diseases of many workers and scientists engaged in animal experimentation. Control measures depend upon characterization of allergens including airborne particles. This study measured the particle size of crude mouse urine and pelt aeroallergens generated in mouse housing rooms and compared them with mouse serum albumin, a defined major allergen. Allergens were detected by specific immunological methods. Most crude and defined allergens (74.5-86.4%) concentrated on a filter with a retention size greater than 7 microns. In distrubed air, allergen concentration increased 1.4 (albumin) to 5 (crude) fold and the proportion of small particles increased from 1.4% in calm air to 4.5% in distrubed air. This information on the generation and size distribution of aeroallergens will be important in the development of effective counter measures.

Strain differences in the early development of the thymus-dependent cells: precocity of T lineage cells in AKR mice as compared to those in C3H mice

Early development of T lineage cells were compared between AKR and C3H mice by using two experimental strategies--neonatal thymectomy (NTx) and bone marrow transplantation (BMT)--between these two strains of mice. After NTx, AKR mice developed less wasting disease and showed better maintenance of several T cell functions. In addition, the response of neonatal spleen cells to PHA and ConA was much greater in AKR mice than in C3H mice. Further, when AKR mice were used as recipients of BMT, cell numbers recovered from thymuses between 2 and 7 weeks after reconstitution were consistently much greater (about 10 times greater) than those from chimeras where C3H mice were used as recipients, regardless of the donor strains of bone marrow cells. However, 4 weeks after BMT the proliferative responses to ConA were consistently higher in the donor-derived thymocytes from chimeras where AKR mice were used as bone marrow donors than in those from chimeras in which C3H were donors. The present findings suggest that these differences may be attributed to characteristics of recipient microenvironment (e.g., thymic stroma) which maintain developing thymocytes and supply them to the peripheral lymphoid tissue. Alternatively the differences may to some degree also be attributable to characteristics of the thymic progenitors themselves, which may determine the rates of maturation of thymocyte functions.

Intraepithelial lymphocytes contain virus-specific, MHC-restricted cytotoxic cell precursors after gut mucosal immunization with reovirus serotype 1/Lang

Reovirus 1 has been intraduodenally administered to mice to determine whether virus-specific cytotoxic cells can be elicited within the intestinal epithelium. We have found that reovirus-stimulated, but not control mice, generate virus-specific cytotoxic effector cells when isolated intraepithelial lymphocytes are restimulated in vitro. These effector cells are restricted by major histocompatibility complex (MHC) class I determinants and thus appear to utilize the T cell antigen receptor and to be of the T cell lineage. These results raise the possibility that cytotoxic T lymphocytes (CTL) may be an important component of the host immune response in the intestinal epithelium.

[Natural killer activity of the splenocytes in C3HA strain mice during 20-methylcholanthrene-induced carcinogenesis]

The induction of tumor in C3HA mice after intramuscular injection with 20-methylcholanthrene is accompanied by a decrease in natural antitumor resistance. This conclusion is based on the observation of the decreased natural killer activity per total number of splenocytes, from the time of carcinogen application till the appearance of tumor nodes.

Adoptive transfer of early and late delayed-type hypersensitivity reactions mediated by human T cells

Human T cells activated by antigen in vitro mediated both the 2-hour and 24-hour phases of delayed-type hypersensitivity (DTH) when transferred into the mouse footpad. The passively transferred human DTH was similar to murine DTH by kinetics, vasoactive amine dependence, and histologic criteria. These results offer a functional assay for determining whether human T cells are activated by viral or tumor antigens.

Feeding trinitrochlorobenzene inhibits development of hapten-specific cytotoxic T lymphocytes by interfering with helper T-cell function

The development of hapten-specific cytotoxic T lymphocytes (CTLs) in mice that were made tolerant by administering the hapten trinitrochlorobenzene (TNCB) intragastrically was examined. The generation of CTL specific for hapten-modified self-antigens in vivo was reduced in animals fed TNCB three times at weekly intervals prior to immunization for CTLs. In addition, splenic cells from hapten-fed mice were unable to develop CTLs in vitro. The inhibition of CTL formation was strictly trinitrophenyl-self-specific as responses to fluorescein isothiocyanate-self- or allogeneic stimulators were fully developed. Limiting dilution analyses revealed that the lack of development of CTL in hapten-fed mice was not attributable to a diminution in the frequency of precursor CTL specific for hapten altered self-antigen. By contrast, the inability of spleen cells of hapten-fed mice to produce CTLs in vitro was reversed by incorporating Lyt1+ cells from normal mice or preformed helper lymphokines into culture. That the nonresponsivity in hapten-fed mice was attributable to nonfunctioning helper cells became additionally evident when splenic L3T4+ cells from hapten-fed mice, in contrast to those from normal mice, were found to be unable to assist normal Lyt2+ splenic cells develop hapten-specific CTLs. Furthermore, fed-L3T4+ cells were ruled out to be directly suppressive of CTL production. This work illustrates that hapten-specific helper T-cell function becomes defective following orally administered hapten and that this deficit contributes to suppression of hapten-specific CTL production.

Inhibition of activated nonresponder C3H/HeJ lymphocytes by lipopolysaccharide endotoxin

The B lymphocytes and macrophages of lipopolysaccharide (LPS) nonresponder C3H/HeJ mice were found to respond to certain R types of LPS endotoxin in a fashion resembling that ordinarily seen with the cells from normal responder mice. DNA synthesis, polyclonal antibody synthesis, and interleukin-1 activity were stimulated by Bordetella pertussis LPS and Salmonella minnesota R595 LPS, although to a lesser extent than with responder cells. Mitogenesis stimulated by both LPSs was inhibited by polymyxin B; this finding provided evidence that any trace endotoxin-associated proteins were not responsible for the activity. Of particular interest was the finding that wild-type smooth LPS actually inhibited activation of the C3H/HeJ B cells not only by the LPS but also by mitogenic proteins, including purified protein derivative of tuberculin. The nonspecific nature of this inhibition and the fact that maximal inhibition occurred some 9 to 12 h into the culture period suggested that the proliferation of the B cells was affected by smooth-type LPS in a manner heretofore unrecognized. These findings permit a new approach to the study of how LPS endotoxin affects cells of the immune system.

Molecular characterization of the C3HfB/HeN H-2Kkm2 mutation. Implications for the molecular basis of alloreactivity

The C3HfB/HeN (C3Hf) mouse strain expresses an H-2Kk molecule, previously denoted H-2Kkv1, that is structurally and functionally distinct from H-2Kk of the parental C3H strain. By molecular genetic analysis, we demonstrate that the C3Hf H-2K gene carries a homozygous coding region mutation relative to the C3H allele, revealing that C3Hf meets the requirements for assignment of a mutant haplotype, H-2km2. C3Hf H-2Kkm2 bears a single clustered substitution of four nucleotides within 14 contiguous nucleotides in exon 3. Since this sequence also is present intact at the homologous position in H-2Dk of both C3H and C3Hf, the origin of the H-2Kkm2 mutation is consistent with a nonreciprocal sequence transfer from the H-2Dk donor gene, analogous to the mechanism proposed for generation of the H-2Kb mutations. The H-2Kkm2 mutation encodes three clustered amino acid substitutions, at positions 95, 98, and 99, that map to one of the large beta strands at the bottom of the peptide antigen binding cleft of the H-2Kkm2 molecule. The nature and location of these amino acid substitutions are unique relative to any other known H-2 mutant or HLA variant, and underscore the importance of the beta-pleated sheet in influencing CTL recognition. These results indicate that H-2Kkm2 alloantigenicity may derive largely from altered presentation of self cellular peptides.

Effect of the gastrointestinal microflora on induction and maintenance of oral tolerance to ovalbumin in C3H/HeJ mice

The effect of the digestive microflora on oral tolerance to ovalbumin was studied by using axenic (germfree) and conventional C3H/HeJ mice. In contrast to reported results of studies with sheep erythrocytes, oral administration of ovalbumin induced tolerance in axenic mice, but the maintenance of tolerance was found to be of shorter duration than was with conventional mice. These data indicate that the contribution of the microflora to oral tolerance depends on the antigen used.

Clearance of different strains of Mycoplasma pulmonis from the respiratory tract of C3H/HeN mice

Pathogen-free C3H/HeN mice were exposed by aerosol to Mycoplasma pulmonis PG34(ASH), UAB 5782C, M1, UAB T, or UAB CT, and clearance of mycoplasmas from the nasal passages, trachea, and lungs was determined during the first 72 h postinoculation (PI). There were differences among strains of mycoplasmas in physical removal of organisms and in killing by nonspecific factors in the nasal passages and trachea. The avirulent strain, PG34(ASH), was quickly removed from the nasal passages and trachea. Physical removal of the other mycoplasmal strains occurred slowly, with 60 to 89% of the radioactive label remaining in the nasal passages and trachea even after 72 h. There were significant differences in killing among mycoplasmal strains by nonspecific host mechanisms in the nasal passages, trachea, and lungs. Strain UAB T was quickly killed at all levels of the respiratory tract. Strains UAB 5782C and M1 were killed at all three sites by 2 to 4 h PI. The most virulent strain, UAB CT, was killed much more slowly than the other strains. However, there was no statistical difference in the relative numbers of mycoplasmas present in the lungs at 72 h PI among strains UAB CT, UAB 5782C, and M1. These studies showed that the different mycoplasmal strains were cleared from the respiratory tract by different mechanisms and suggest that the differences in virulence among the mycoplasma strains can be explained, in part, by the differences in elimination of the organisms from the respiratory tract by nonspecific host defense mechanisms.

Suppression of genetic resistance to bone marrow grafts and natural killer activity by administration of fat emulsion

Graft rejection is one of the major obstacles to successful bone marrow transplantation (BMT). If resistance to marrow grafting could be avoided, BMT could be used widely in treatment of hematological and immunological disorders. There has been evidence that natural killer (NK) cells play a major role in genetic resistance to BMT and that macrophages are also involved in genetic resistance. Agents toxic to macrophages such as silica and carrageenan have been found to have a suppressive effect on genetic resistance to BMT. Parenteral fat emulsions are known to accumulate in macrophages and to impair various functions of macrophages and those of the reticuloendothelial system. We show here that the administration of a fat emulsion, Intralipos 20%, to recipient mice can suppress genetic resistance to bone marrow grafts and NK cell activity probably through the impairment of the macrophage function. The administration of the fat emulsion might be a new tactic in conditioning protocols for human BMT in the future.

Histocompatibility antigen changes associated with pink-eyed dilute (p) mutations

The tight linkage between the H-4 histocompatibility locus and the pink-eyed dilute (p) locus raises the possibility that a single gene is responsible for both a histocompatibility antigen and coat color phenotype. To examine this possibility, we have investigated the effects of a spontaneous coat color mutation, pink-eyed unstable (pun), which occurred at the p locus in the C57BL/6J inbred strain, on histocompatibility antigen phenotype. Skin grafts were transplanted from two independently maintained B6-pun substrains to coisogenic, wild-type C57BL/6 recipients; graft rejection uniformly commenced at 6-7 weeks but did not culminate in complete graft destruction as observed in other cases of "crisis" rejection. Neither the onset of rejection time nor the intensity of rejection could be accelerated by introducing new H-2 haplotypes into the wild-type recipients. These results suggested that the pun allele was associated with a histocompatibility antigen not shared with C57BL/6. The pun allele is characterized by a relatively high frequency of reversion to wild-type. Therefore, skin grafts from B6-pun donors were transplanted to homozygous, revertant (+/+) recipients which were subline-matched with the donors; these grafts underwent crisis rejection with the same time of onset of rejection as observed with C57BL/6 recipients. These observations indicate that a new histocompatibility antigen is associated with the pun mutation and is lost upon reversion to wild type; this association is the first demonstration of a link between histocompatibility and coat color phenotypes.

Activation of thymocyte responses to interleukin-1 by zinc

In vitro proliferative responses of murine thymocytes to interleukin-1 are enhanced by supplementing the cultures with the trace nutrient zinc. Zine not only enhances the responses of cells suboptimally activated by PHA but can also prime the cells to respond to IL-1 in the absence of activation by PHA. Zinc affects the early stages of the proliferative response. The data suggest that zinc may enhance the cellular uptake of IL-1 or may facilitate enzymatic steps subsequent to IL-1 binding.