Lesional activation of Tc 17 cells in Behçet's disease and psoriasis supports HLA-class I-mediated autoimmune responses

BACKGROUND

Behçet's disease (BD) presents with lymphocytic and neutrophilic vasculitis of unknown aetiology. HLA-B*51 ERAP1 and IL12R/IL23R are genetic risk factors. IL-23 regulates IL-17A, which controls recruitment and activation of neutrophils.

OBJECTIVES

To determine pathological changes in BD skin lesions related to the complex genetic predisposition METHODS: We characterised the expression of IL-17A and IL-23A in various cell types by immunohistological double staining of sections from papulopustular skin lesions (PPL) of acute attacks of BD and lesions of psoriasis vulgaris (PV), another HLA-class I-associated T-cell mediated autoimmune disease in which excessive T-cell derived IL-17A production promotes neutrophil activation.

RESULTS

We found that in BD lesions, as in psoriasis, actively expanding CD8⁺ T cells were the predominant source of IL-17A. IL-17A⁺ CD8⁺ T (Tc17) cells outnumbered infiltrating IL-17A⁺ CD4⁺ T cells. Unlike the epidermal localisation of CD8⁺ T cells in psoriasis, Tc17 cells in BD lesions infiltrated mainly the perivascular tissue and also the blood vessel walls of dermis and subcutaneous tissue. They colocalised with a marked IL-23A expression by CD11c⁺ dendritic cells (DCs) and CD68⁺ macrophages. IL-17A expression was associated with extensive recruitment of neutrophils around blood vessels that formed neutrophil extracellular traps (NETs).

CONCLUSIONS

In BD, the genetic predisposition may mediate antigen-specific activation and differentiation of a T_c 17 response, possibly targeting endothelial antigens. Neutrophils recruited by IL-17A in this process may enhance tissue damage by extensive NET formation (NETosis). Thus, the IL-23/IL-17 axis presumably controls neutrophilic inflammation in BD vasculitis in the context of a predominant antigen-specific CD8⁺ T-cell response.

Prevalence of and factors associated with frailty and disability in older adults from China, Ghana, India, Mexico, Russia and South Africa

BACKGROUND

The severe burden imposed by frailty and disability in old age is a major challenge for healthcare systems in low- and middle-income countries alike. The current study aimed to provide estimates of the prevalence of frailty and disability in older adult populations and to examine their relationship with socioeconomic factors in six countries.

METHODS

Focusing on adults aged 50+ years, a frailty index was constructed as the proportion of deficits in 40 variables, and disability was assessed using the World Health Organization Disability Assessment Schedule (WHODAS 2.0), as part of the Study on global AGEing and adult health (SAGE) Wave 1 in China, Ghana, India, Mexico, Russia and South Africa.

RESULTS

This study included a total of 34,123 respondents. China had the lowest percentages of older adults with frailty (13.1%) and with disability (69.6%), whereas India had the highest percentages (55.5% and 93.3%, respectively). Both frailty and disability increased with age for all countries, and were more frequent in women, although the sex gap varied across countries. Lower levels of both frailty and disability were observed at higher levels of education and wealth. Both education and income were protective factors for frailty and disability in China, India and Russia, whereas only income was protective in Mexico, and only education in South Africa.

CONCLUSIONS

Age-related frailty and disability are increasing concerns for older adult populations in low- and middle-income countries. The results indicate that lower levels of frailty and disability can be achieved for older people, and the study highlights the need for targeted preventive approaches and support programs.

Effect of preorganization on the affinity of synthetic DNA binding motifs for nucleotide ligands

Triplexes with a gap in the purine strand have been shown to bind adenosine or guanosine derivatives through a combination of Watson-Crick and Hoogsteen base pairing. Rigidifying the binding site should be advantageous for affinity. Here we report that clamps delimiting the binding site have a modest effect on affinity, while bridging the gap of the purine strand can strongly increase affinity for ATP, cAMP, and FAD. The lowest dissociation constants were measured for two-strand triple helical motifs with a propylene bridge or an abasic nucleoside analog, with Kd values as low as 30 nM for cAMP in the latter case. Taken together, our data suggest that improving preorganization through covalent bridges increases the affinity for nucleotide ligands. But, a bulky bridge may also block one of two alternative binding modes for the adenine base. The results may help to design new receptors, switches, or storage motifs for purine-containing ligands.

The ubiquitin-conjugating enzymes UBE2N, UBE2L3 and UBE2D2/3 are essential for Parkin-dependent mitophagy

Depolarized mitochondria are degraded by mitophagy in a process that depends on the Parkinson's disease gene products PINK1 and Parkin. This is accompanied by ubiquitylation of several mitochondrial substrates. The roles of E2 ubiquitin-conjugating enzymes (UBE2) in mitophagy are poorly understood. Here, we investigate a set of UBE2 enzymes that might regulate Parkin-mediated mitophagy. Knockdown of the E2 enzymes UBE2N, UBE2L3 or UBE2D2 and UBE2D3 (UBE2D2/3) significantly reduced autophagic clearance of depolarized mitochondria. However, this did not interfere with mitochondrial PINK1 stabilization and Parkin translocation. UBE2N knockdown prevented specifically K63-linked ubiquitylation at mitochondrial sites. Nevertheless, polyubiquitin and p62 (officially known as SQSTM1) were still found on mitochondria after individual UBE2 knockdown. Knockdown of all of these UBE2s together significantly reduced mitochondrial polyubiquitylation and p62 recruitment. Moreover, reduced ubiquitylation of mitofusins, the mitochondrial import receptor subunits TOM20 and TOM70, the voltage-dependent anion channel protein 1 and Parkin was observed in cells silenced for all of these UBE2s. A version of Parkin with a mutation in the active site (C431S) failed to ubiquitylate these mitochondrial substrates even in the presence of UBE2s. We conclude that UBE2N, UBE2L3 and UBE2D2/3 synergistically contribute to Parkin-mediated mitophagy.

Folding and self-assembly of the TatA translocation pore based on a charge zipper mechanism

We propose a concept for the folding and self-assembly of the pore-forming TatA complex from the Twin-arginine translocase and of other membrane proteins based on electrostatic "charge zippers." Each subunit of TatA consists of a transmembrane segment, an amphiphilic helix (APH), and a C-terminal densely charged region (DCR). The sequence of charges in the DCR is complementary to the charge pattern on the APH, suggesting that the protein can be "zipped up" by a ladder of seven salt bridges. The length of the resulting hairpin matches the lipid bilayer thickness, hence a transmembrane pore could self-assemble via intra- and intermolecular salt bridges. The steric feasibility was rationalized by molecular dynamics simulations, and experimental evidence was obtained by monitoring the monomer-oligomer equilibrium of specific charge mutants. Similar "charge zippers" are proposed for other membrane-associated proteins, e.g., the biofilm-inducing peptide TisB, the human antimicrobial peptide dermcidin, and the pestiviral E(RNS) protein.

Structural role of the conserved cysteines in the dimerization of the viral transmembrane oncoprotein E5

The E5 oncoprotein is the major transforming protein of bovine papillomavirus type 1. This 44-residue transmembrane protein can interact with the platelet-derived growth factor receptor β, leading to ligand-independent activation and cell transformation. For productive interaction, E5 needs to dimerize via a C-terminal pair of cysteines, though a recent study suggested that its truncated transmembrane segment can dimerize on its own. To analyze the structure of the full protein in a membrane environment and elucidate the role of the Cys-Ser-Cys motif, we produced recombinantly the wild-type protein and four cysteine mutants. Comparison by circular dichroism in detergent micelles and lipid vesicular dispersion and by NMR in trifluoroethanol demonstrates that the absence of one or both cysteines does not influence the highly α-helical secondary structure, nor does it impair the ability of E5 to dimerize, observations that are further supported by sodium dodecylsulfate polyacrylamide gel electrophoresis. We also observed assemblies of higher order. Oriented circular dichroism in lipid bilayers shows that E5 is aligned as a transmembrane helix with a slight tilt angle, and that this membrane alignment is also independent of any cysteines. We conclude that the Cys-containing motif represents a disordered region of the protein that serves as an extra covalent connection for stabilization.

Deletion of the late cornified envelope genes LCE3B and LCE3C may promote chronic hand eczema with allergic contact dermatitis

BACKGROUND

Genetically determined defects in epidermal skin barrier function may contribute to the development of irritant and/or allergic contact dermatitis in chronic hand eczema (CHE).

OBJECTIVES

To assess whether a deletion in the late cornified envelope genes LCE3B and LCE3C may constitute a genetic predisposition for the development of CHE or any of its subtypes.

PATIENTS AND METHODS

A total of 153 German patients with clearly defined CHE subtypes and 268 healthy individuals were screened for the deletion LCE3C_LCE3B-del by allele-specific polymerase chain reaction.

RESULTS

Classification of the patients by etiologic subtypes revealed an association between the LCE3C_LCE3B-del allele and CHE due to allergic contact dermatitis. In this subtype, 19/37 patients (51.4%) were homozygous deletion carriers, 11/37 (29.7%) were heterozygous carriers, and just 7/37 (18.9%) were wild-type individuals. Compared to the other CHE subgroups and the healthy control group (homozygous, 88/268 [32.83%]; heterozygous, 133/268 [49.63%]; and wild-type, 47/268 [17.54%]), the prevalence of LCE3C_LCE3B-del in these patients reached statistical significance (P = .03977), as did homozygous deletion carrier status (P = .01044 for other subtypes and P = .02695 for controls).

CONCLUSIONS

A deletion of LCE genes may promote the development of allergic contact dermatitis, which is a form of CHE involving delayed-type hypersensitivity.

Filaggrin mutations may confer susceptibility to chronic hand eczema characterized by combined allergic and irritant contact dermatitis

BACKGROUND

The pathogenesis of chronic hand eczema (CHE) is multifactorial and involves both endogenous predisposition and environmental triggers.

OBJECTIVES

Filaggrin is a structural protein of the cornified envelope and important for the formation of the epidermal skin barrier. The aim of this investigation was to evaluate the role of mutations in the filaggrin gene (FLG) in the development of CHE.

METHODS

In total, 122 German patients with clearly defined CHE subtypes were screened for the FLG variants R501X and 2282del4 by polymerase chain reaction and restriction enzyme digest analysis. The prevalence of these variants in CHE patients was compared with that in 95 healthy individuals.

RESULTS

Overall, allele frequency and the number of mutation carriers were similar in both the CHE and control groups. When classified according to clearly defined CHE subtypes, however, the nonfunctional FLG variants showed an association with CHE involving an aetiological combination of contact allergy and irritant factors [P = 0.04; P (exact test) = 0.06; P (difference in rates) = 0.09; 95% confidence interval (CI) 0-56.8)], or with excessive daily exposure to water and irritants [P = 0.003; P (difference in rates) < 0.001; 95% CI 29.3-67.9].

CONCLUSION

Heterozygosity for nonfunctional mutations in the FLG gene may contribute to the manifestation and maintenance of a particular CHE subtype that is characterized by the combination of allergic and irritant contact dermatitis.

Dominant lesional T cell receptor rearrangements persist in relapsing psoriasis but are absent from nonlesional skin: evidence for a stable antigen-specific pathogenic T cell response in psoriasis vulgaris

In a previous study we reported that clonally expanded T cell receptor beta-chain rearrangements characterized the T cell receptor usage in skin lesions of psoriasis vulgaris and indicated antigen-specific T cell selection. To assess the relevance of clonal T cell expansion for disease progression, we now determined if select clonal T cell receptor rearrangements persisted over time and were present in nonlesional skin. Sequential biopsies were taken from psoriatic skin lesions of two patients. V-D-J junctional regions of T cell receptor beta-chain variable region gene families 2, 3, 6, 13S1, and BV17 were cloned and sequenced, as these particular BV gene families are preferentially selected in psoriatic skin lesions. The lesional T cell receptor rearrangements were compared with the T cell receptor usage in nonlesional skin and in blood. Several T cell receptor beta-chain rearrangements with high transcript frequency in the first lesional biopsy were again found in sequential lesional biopsies taken as much as 3 y later from psoriasis relapses. Only T cell receptor beta-chain rearrangements with low transcript abundance showed variability in that several clones appeared for the first time or disappeared. Although nonlesional skin also exhibited a restricted T cell receptor usage with clonal T cell receptor rearrangements, the T cell receptor usage in lesional and nonlesional skin differed nearly completely. The select lesional recurrence of identical T cell receptor rearrangements reveals that inflammation in psoriasis involves the same clonally expanded T cell populations and the same antigens over prolonged periods of time. It hereby suggests that specifically recruited and locally expanded T cell clones are permanently involved in psoriatic inflammation and may play a crucial part in disease perpetuation.

Analysis of the TCRBV repertoire of T cells in normal, human skin: evidence for a restricted diversity

Alpha beta T cells constitute an important component in the first line of immunologic defense in human skin. In order to determine the local selection forces driving T cell diversity, we studied the T cell receptor repertoire in normal human skin and compared it with that of matched blood samples. Using semiquantitative reverse transcription-polymerase chain reaction the expression of T cell receptor beta-chain V genes was determined. The majority of skin, but not blood T cells, revealed a bias towards usage of T cell receptor beta-chain V2 and V6. Whereas sequencing of T cell receptor beta-chain V2 and V6 polymerase chain reaction products showed a heterogeneous clonal distribution within these beta-chain V gene families, the analysis of other selected either over- or underrepresented beta-chain V gene families (BV3, BV12, BV13S1, BV17) revealed numerous identical T cell receptor beta-chain V transcript sequences that were not detected in blood. Restricted T cell receptor diversity in terms of beta-chain V gene preferences or clonal expansion was observed in skin samples of donors from all ages (0.5-87 y). Hence, the repertoire of T cells in normal human skin is apparently subjected to skin-specific selection throughout life. According to our data, this process could involve superantigens, which favor polyclonal accumulation of T cells using certain beta-chain V genes, as well as antigens, which induce clonal T cell expansion. Our results furthermore indicate, that T cell receptor beta-chain V repertoire restrictions do not necessarily result from disease-associated activation of the skin immune system, but could reflect regular mechanisms of immunologic homeostasis within the epithelial surface of the body.

Selection of conserved TCR VDJ rearrangements in chronic psoriatic plaques indicates a common antigen in psoriasis vulgaris

Psoriasis vulgaris is a common HLA-associated inflammatory skin disease. Although its etiology is still unknown, it is thought to involve T cell-mediated inflammatory mechanisms. In examining the lesional psoriatic TCR beta chain (TCRB) usage in a pair of identical twins concordant for psoriasis, we observed repetitive TCR VDJ rearrangements which indicated antigen-specific oligoclonal T cell expansion. Several of these TCRB rearrangements were identical or highly homologous in the amino acid composition of the complementarity determining region 3 (CDR3), suggesting that T cells with these TCR might be important for disease manifestation. This conclusion was strengthened by TCR analysis of other psoriasis patients. Several repetitive lesional TCRB rearrangements were found that were similar to the conserved CDR3 seen in the twins. Since TCR antigen specificity is largely determined by the beta chain CDR3, selection of T cells with conserved TCRB CDR3 motifs could indicate the presence of a common antigen as a major target of the lesional psoriatic immune response.

Evidence for an antigen-specific cellular immune response in skin lesions of patients with psoriasis vulgaris

Psoriasis vulgaris is an inflammatory skin disease characterized by excessively increased keratinocyte proliferation. Several lines of evidence support the idea that T cells infiltrating psoriatic skin lesions play a vital role in the pathogenesis of the disease. To establish whether lesional accumulation and activation of T lymphocytes reflect a specific local immune response, the TCR beta-chain variable (V beta) region gene usage was studied in chronic psoriatic plaques, normal skin, and paired blood lymphocytes. By semiquantitative PCR, we found that overexpression of either or both V beta 2 and V beta 6 gene families characterized the TCR repertoires of normal skin and psoriatic skin lesions. However, sequence analysis of the complementarity-determining region 3 (CDR3) of these V beta gene families demonstrated a marked TCR oligoclonality only in psoriatic lesions, not in normal skin or in blood lymphocytes. The amino acid sequences of the lesional TCR clones revealed that certain conserved junctional motifs were shared by different patients. A second biopsy taken from one of the psoriasis patients 18 mo later from a different anatomical site disclosed that the same TCR clones were again dominating. These data suggest that lesional psoriatic T lymphocytes expressing the prevailing TCR V beta genes represent an oligoclonal T cell subset that expanded from a few progenitor T cells in response to Ag in the skin of psoriasis patients. They are derived from a polyclonal T cell population that, by the expression of V beta 2 or V beta 6 TCR, appears to be predisposed for homing to the skin.

Evidence for an antigen-specific cellular immune response in skin lesions of patients with psoriasis vulgaris

Psoriasis vulgaris is an inflammatory skin disease characterized by excessively increased keratinocyte proliferation. Several lines of evidence support the idea that T cells infiltrating psoriatic skin lesions play a vital role in the pathogenesis of the disease. To establish whether lesional accumulation and activation of T lymphocytes reflect a specific local immune response, the TCR beta-chain variable (V beta) region gene usage was studied in chronic psoriatic plaques, normal skin, and paired blood lymphocytes. By semiquantitative PCR, we found that overexpression of either or both V beta 2 and V beta 6 gene families characterized the TCR repertoires of normal skin and psoriatic skin lesions. However, sequence analysis of the complementarity-determining region 3 (CDR3) of these V beta gene families demonstrated a marked TCR oligoclonality only in psoriatic lesions, not in normal skin or in blood lymphocytes. The amino acid sequences of the lesional TCR clones revealed that certain conserved junctional motifs were shared by different patients. A second biopsy taken from one of the psoriasis patients 18 mo later from a different anatomical site disclosed that the same TCR clones were again dominating. These data suggest that lesional psoriatic T lymphocytes expressing the prevailing TCR V beta genes represent an oligoclonal T cell subset that expanded from a few progenitor T cells in response to Ag in the skin of psoriasis patients. They are derived from a polyclonal T cell population that, by the expression of V beta 2 or V beta 6 TCR, appears to be predisposed for homing to the skin.

T lymphocytes derived from skin lesions of patients with psoriasis vulgaris express a novel cytokine pattern that is distinct from that of T helper type 1 and T helper type 2 cells

In various immunological disorders the pathomechanisms of tissue damage are causally associated with specific patterns of locally produced cytokines. To study the molecular and cellular mechanisms involved in the manifestation of psoriasis vulgaris we have assessed the cytokine mRNA profile expressed in lesional psoriatic skin and in T cell clones (TCC) that were established from skin lesions of patients with psoriasis. As demonstrated by use of the polymerase chain reaction (PCR), psoriasis lesions consistently exhibit transcription of a complex pattern of cytokines. It includes mediators selectively produced by T lymphocytes [interferon (IFN)-gamma, tumor necrosis factor (TNF)-beta, interleukin (IL)-2, IL-3 and IL-5] as well as cytokines secreted by various cell types [transforming growth factor (TGF)-alpha/-beta, TNF-alpha, IL-6/-8 and granulocyte-macrophage-colony stimulating factor], while IL-4 is missing. With the exception of TGF-alpha, this cytokine profile was also observed in lesional psoriatic T cell clones yielding supernatants mitogenic for keratinocytes in vitro (MTCC), but not in T cell clones yielding supernatants that inhibited keratinocyte proliferation (STCC). The congruent cytokine expression of psoriatic skin lesions and MTCC emphasizes that inflammation in psoriasis is driven by a sofar unrecognized regulatory T cell subset that may serve to control epidermal regeneration and convey immunosurveillance over epithelial surfaces. It is characterized by the combined expression of IFN-gamma, TGF-beta, IL-2 and IL-5 in the absence of IL-4 and by its selective capacity to enhance keratinocyte proliferation. This newly defined combination of regulatory properties of a distinct T cell population cannot be reconciled with an immune response of the T helper cells (TH)0, TH1 or TH2 type.

The activity of S-thiomethyl modified creatine kinase is due to the regeneration of free thiol at the active site

Creatine kinase modified by S-methyl methanethiosulfonate and devoid of reactive thiol group has been reported to retain about 18-40% of the activity of the native enzyme. It has now been found that during the reaction catalyzed by the modified enzyme the rate increases with time and if the reaction is allowed to continue sufficiently long, the enzyme eventually recovers full activity. The presence of substrates is not required for the reactivation as suitable dilution after removal of MMTS in excess leads to complete reactivation of the MMTS modified enzyme with the simultaneous regeneration of reactive thiol per each dimeric molecule as shown by determinations with DTNB and IAN. The addition of MMTS during the course of reactivation again inactivates the reactivated enzyme. The activity recovery is therefore due to the regeneration of reactive thiol and it appears that the active-site thiols are essential for the activity of rabbit muscle creatine kinase.

T cell clones from psoriasis skin lesions can promote keratinocyte proliferation in vitro via secreted products

Psoriasis vulgaris has been recognized lately as an immunologically mediated inflammatory skin disease. To analyze the pathogenetic role of T lymphocytes in the generation of psoriatic skin lesions, 105 T cell clones (TCC) and 10 T cell lines (TCL) were differentially isolated from dermis and epidermis of psoriatic skin specimens. Supernatants prepared from these T cells were studied for their effects on keratinocyte proliferation in vitro. Conditioned media from 14 of 77 epidermal TCC, 7 of which were CD8+, and from 8 of 28 dermal TCC, 5 of which were CD8+, reproducibly enhanced keratinocyte proliferation, with more pronounced mitogenic activities found in dermal TCC. Another 9 epidermal and 3 dermal TCC did not affect keratinocyte growth and supernatants from the remaining clones, as well as from the 5 epidermal and 5 dermal TCL, inhibited keratinocyte replication to varying degrees. Both mitogenic and suppressive activities were largely abolished by addition of an antiserum to interferon-gamma (IFN-gamma), while addition of epidermal growth factor or irradiated psoriatic TCL had little effect on the activities of the supernatants. These studies reveal that a subpopulation of lesional psoriatic T lymphocytes is capable of enhancing keratinocyte proliferation in vitro via secreted products. Their mitogenic capacity most likely requires IFN-gamma, but the ultimate effect is apparently determined by the presence of additional cytokines. Activation of T cells secreting such combinations of factors in vivo may contribute to the keratinocyte alterations characteristic of psoriatic skin lesions.

[Blunt abdominal trauma--sonographic findings]

Results of sonographic investigations from 435 patients with blunt abdominal trauma or polytrauma admitted to a traumatology service are given. Complete evaluation of the abdominal organs was impeded in 94 cases by meteorism or other factors like immobility or hyperactivity of inebriated patients. Evaluation of the pancreas was inhibited in most of these cases. In 33 cases lesions of an organ could be verified during surgery. In one case the false positive diagnosis of "spleen rupture" led to operation. Suspicion of free fluid in the abdominal cavity (5 cases) could not be verified in any of the cases during a second investigation and was deemed to be negligible. Rupture of the spleen was diagnosed in 12 out of 14 cases, renal contusion in 7 out of 7 cases. Liver-, bowel- and mesenteric lesions were occasionally diagnosed indirectly (evidence for free fluid). Quality assessment did not reveal a difference between day time or nocturnal work shifts provided the investigators were experienced in sonography.

Immunocytochemical studies on several developmental stages of Dipetalonema viteae (Filarioidea)

The binding of antibodies to infective larvae (L3), eggs, uterine contents and blood microfilariae was demonstrated by light microscopy employing the peroxidase-antiperoxidase (PAP) method. Antigen-antibody reactions were located on the shell of filarial eggs as well as on the cuticle and the interior of L3 and microfilariae. Using sera from Meriones unguiculatus, Mastomys natalensis and golden hamsters infected with D. viteae obtained at 7, 14, 21 and 28 weeks p.i. it was observed that the intensity of the immunostaining on several developmental stages of the filariae decreased with increasing duration of infection. This effect was more pronounced in the case of M. unguiculatus and M. natalensis than in the case of golden hamsters. For detection of surface antigenicity the simple procedure of drying the test material on microscopic slides proved to be time saving and equally specific as compared to the embedding in Epon of the filarial stages and the successive preparation of semithin sections. However, embedded filarial stages presented more intensive immunostaining than nonembedded stages. Moreover, sections allowed to demonstrate antigen-antibody reactions on the cuticle as well as inside the body cavity of the stages.

Immunocytochemical and ultrastructural studies on Dipetalonema viteae (Filarioidea)

The antigenic properties of adult male and female of Dipetalonema viteae were studied by immunocytochemistry. Using antisera of the rodents Meriones unguiculatus and Mastomys natalensis infected with D. viteae, the binding of antibodies to sections of filariae embedded in Epon was assayed by the peroxidase-antiperoxidase (PAP) technique and by electron microscopy. The optimal staining intensity was obtained with an antiserum dilution of 1:5000. Control sera were obtained from sex and age matched uninfected animals. Female D. viteae showed maximal antigen-antibody reactions within the uterus: in the inner uterus wall, in the "nutrient channels" between the maturing eggs and the differentiating microfilariae, on the eggshells, in the cuticula of microfilariae and in the spermatheca on the cell membrane of the mature spermatozoa. Male filariae showed binding of antibodies in the vesicula seminalis: in the nucleus and the nuclear membrane of primary spermatocytes and on maturing spermatids. Less pronounced antigen-antibody reactions in the cuticula, muscle and intestine were observed in both sexes. The PAP-technique offers significant improvements in comparison with other techniques, e.g., immunofluorescence, used to detect antigens on filariae: the PAP-technique has an increased sensitivity with a concomitant reduction in nonspecific background and can be used for both light and electron microscopy; moreover, PAP-treated tissues can be stored indefinitely at room temperature.

Protein composition of various developmental stages of dipetalonema viteae (Filarioidea)

The protein composition of various developmental stages of Dipetalonema viteae was analysed on polyacrylamide slab gels in the presence of sodium-dodecylsulphate. When the total proteins of adult male and female parasites, microfilariae, eggs, and third-stage larvae were compared, apparent qualitative similarities between mature and immature filariae were observed. However, several stage specific components were also identified.

Immunocytochemical studies on Dipetalonema viteae (Filarioidea)

The antigenic properties of adult male and female worms of the nematode Dipetalonema viteae (Filarioidea) were studied by immunocytochemistry. Using sera of rodents infected with this parasite, the binding of antibodies to sections of worms embedded in Epon was assayed by the peroxidase-antiperoxidase (PAP) technique and by light microscopy. In female worms antigen-antibody reactions were located in the uterine fluid, the inner uterus wall, the circumference of the microfilariae and in the egg shell. Male D. viteae showed binding of antibodies in the vesica seminalis and in the vas deferens. Both sexes has also less pronounced antigenic activities in cuticula, muscle and intestine.

Vitamin D-dependent calcium-binding protein. Immunochemical studies and synthesis by placental tissue in vitro

A protein similar to rat intestinal calcium-binding protein (CaBP) has been identified in both mouse placenta and mouse small intestine. The mouse protein had a molecular weight of approximately 10,000, exhibited cation-binding properties, and demonstrated immunologic identity with vitamin D-dependent rat CaBP. Under normal dietary conditions, the concentrations of CaBP in mouse placenta and intestine increased 6- and 3-fold, respectively, during the third trimester of pregnancy in parallel with the fetal demands for skeletal mineral. Studies of in vitro protein synthesis indicated that CaBP was synthesized by placental tissue. Slices of mouse or rat placental tissue (12-18-day gestation) were incubated with [3H]leucine and the biosynthesis of placental CaBP was quantified by an immunoprecipitation method using rabbit antiserum to rat intestinal CaBP. Sodium dodecyl sulfate gel electrophoresis of the radioactive immune complex revealed a single 3H-labeled peak corresponding to the molecular weight of rat and mouse CaBP (10,050). The amount of CaBP synthesized by mouse placental tissue was dependent upon gestational age of the placenta and reflected the in vivo changes in placental CaBP content observed during gestation. These data indicate that CaBP is synthesized by placenta and provide an in vitro model for studying the developmental control of placental CaBP synthesis.