Serological cross-reactivity between products of separate I regions

A B10.S(7R) anti-B10.S(9R) serum (anti-IJE ^k C ^d ) contained, as expected, antibodies specific for the I-E-subregion-encoded determinant Ia.7. However, tests on recombinant haplotypes demonstrated a series of unexpected weak extrareactions which could be interpreted to be directed against antigenic determinants encoded in the I-A subregion of the H-2 complex. The same type of extrareaction was observed in eluates from I-A ^s , I-E ^k cells coated with A.TH anti-A.TL (I-A ^s , I-E ^s anti-I-A ^k , I-E ^k ) serum. This reactivity in serum and eluates could be interpreted as cross-reactivity between products of the I-E and I-A subregions.     

Serological cross-reactivity between sporothrix schenckii and various unrelated fungi

The serological cross-reactivity ofSporothrix schenckii with various unrelated fungi was investigated by use of immunodiffusion tests. A rabbit antiS. schenckii serum was obtained, which reacted withCladosporium werneckii, C. carrionii, C. bantianum, Coccidioides immitis, Phialophora jeanselmei, P. gougerotii, P. dermatitidis, Fonsecaea pedrosoi, Aspergillus fumigatus, Histoplasma capsulatum andTrichophyton mentagrophytes, but not withSaccharomyces cerevisiae antigens. The serological determinants responsible for the cross-reactions were suggested to be D-galactosyl residues.     

Serological and skin test cross-reactivity between Histoplasma capsulatum and Oidiodendron kalrai

Guinea pigs were infected with yeast cells ofHistoplasma capsulatum andOidiodendrom kalrai. They were skin tested 6 and 12 weeks post-infection with both homologous and heterologous antigens. There was almost complete skin test cross-reactivity between histoplasmin and oidiodendrin after 12 but not after 6 weeks. There were also strong serologic cross-reactions among 6 different anti-H. capsulatum hyperimmune sera and oidiodendrin. However, cross-reactions among anti-O. kalrai sera and histoplasmin could not be demonstrated.     

Sharing of Ia antigens between species. IV. Interspecies cross-reactivity of monoclonal antibodies directed against polymorphic mouse Ia determinants

The specificity of interspecies Ia cross-reactions has been analyzed by testing a panel of monoclonal antibodies (mAb) to mouse I-E and I-A antigens for reactivity with pig Ia antigens. Our earlier studies showed that mouse anti-I-E alloantisera recognized common determinants on Ia antigens of other species, whereas anti-I-A alloantisera showed much more limited cross-reactivity. These results were confirmed using a panel of 17 anti-I-E mAb, 10 of which were cytotoxic to pig cells. 2D gel electrophoretic analyses of precipitates with these mAb of 35S-labeled, NP40 solubilized pig cells revealed a limited set of protein spots that appeared to be identical to the subset of pig Ia antigens precipitated by A.TH anti-A.TL alloantiserum. Because the cross-reactive mouse sera were produced in mouse strains that do not express an I-E molecule (H-2b and H-2s), it was anticipated that the cross-reacting antibodies would be reactive with the monomorphic determinant of the I-E molecule, Ia.7. However, comparison of the reactivity of these mAb with pig cells and mouse cells revealed that the cross-reactivity on pig cells correlated not with Ia.7 but rather with detection of epitope(s) of the I-E molecule associated with inter-strain polymorphism. Anti-I-A cross-reactions were also detected, but were weaker and more limited. These findings may have implications for the evolution of Ia antigens in mammalian species.     

Serological cross-reactivity betweenKlebsiella pneumoniae K47 andSporothrix species

The serological cross-reactivity ofKlebsiella pneumoniae K47 antiserum with antigens of 11Sporothrix species was investigated by use of immunodiffusion. Cross-reactions occurred withK. pneumoniae K47 and theSporothrix speciesS. schenckii, S. schenckii var.luriei, S. curviconia, andS. inflata.     

Serological cross-reactivity between Strongyloides venezuelensis and Syphacia muris in Wistar rats (Rattus norvegicus)

One of the problems frequently faced in laboratory facilities is the possibility of the natural parasitic infection of lab animals, which can interfere with biomedical research results. The present study aimed to evaluate cross-reactivity among serum samples from Wistar rats (Rattus norvegicus) naturally infected with Syphacia muris and experimentally infected with Strongyloides venezuelensis. Forty rats were divided into four groups of ten animals each. Parasite load was evaluated by quantifying the adult worms from both helminthes species recovered from the intestines and the S. venezuelensis eggs eliminated in feces. Serological cross-reactivity by parasite-specific IgG detection was tested via enzyme linked immunosorbent assay (ELISA), immunofluorescence antibody test (IFAT) and immunoblotting. The results demonstrated that the quantity of S. venezuelensis eliminated eggs and parthenogenetic females decreased significantly in cases of co-infection with S. muris. ELISA revealed 100% cross-reactivity of serum samples from both species against the opposing antigen. IgG cross-reactivity was confirmed by IFAT using tissue sections of S. venezuelensis larvae and adult S. muris. Immunoblotting showed that IgG antibodies from the sera of animals infected with S. muris recognized eight antigenic bands from S. venezuelensis saline extract and that IgG antibodies from the sera of animals infected with S. venezuelensis recognized seven bands from S. muris saline extract. These results demonstrate the serological cross-reactivity between S. muris and S. venezuelensis in infected rats.     

Serological and biological cross-reactivity of class II antigens between mice and humans in antigen-specific T-cell proliferative responses

Many studies have already been reported with regard to the serological cross-reactivities between the polymorphic determinants of murine Ia antigens and human HLA-DR antigens. In this paper, we examined the biological cross-reactivity of the polymorphism of Class II antigens in the xenogeneic antigen-presenting cell (APC)-T-cell interaction. The data indicate that purified protein derivative (PPD)-specific human T cells were not stimulated by PPD-pulsed murine APC from B10.S(9R) which possess I-As and I-Ek molecules serologically cross-reacting with human Class II antigens. On the contrary, B10.S(9R) T cells primed to PPD were stimulated by PPD-pulsed human APC. The failure of the murine APC-human T-cell interaction was not caused by the suppressive effect in culture with ongoing xenogeneic mixed lymphocyte reactions (MLR) or other cell culture conditions. Thus, a hierarchy of antigen-presenting ability in the xenogeneic APC-T-cell interaction was shown to exist.     

Serological analysis of H-2 and Ia molecules with monoclonal antibodies

Five H-2 and seven Ia monoclonal antibodies were tested against a panel of 43 independentH-2 haplotypes (11 of laboratory-mouse and 32 of wild-mouse origin), 33 recombinantH-2 haplotypes, and up to 74 wild mice. All the antibodies gave negative reactions in the PVP hemagglutination tests; all, however, gave positive reaction with some members of the panel in the dye-exclusion cytotoxic test. Four of the antibodies (H-2.m2,Ia.m2, Ia.m5 and Ia.m7) reacted identically to conventional antibodies detecting determinants H-2.2., and Ia-1.2, Ia-1.15, and Ia-5.7, respectively (this statement does not apply to wild mice in which minor differences in reactivity patterns of the corresponding antibodies were found: the reproducibility of these differences, however, could not be checked by absorption). Five other antibodies (H-2.m5, H-2.m3, H-2.m4, Ia.ml, and Ia.m6) had very similar though not identical reactivity patterns to conventional antibodies detecting determinants H-2.5, H-2.11, H-2.25, Ia-1.2, and Ia-1.19, respectively. The last three monoclonal antibodies (H-2.ml, Ia.m3, and Ia.m4) had a reactivity pattern that did not match those of any known conventional antibodies. The near identity or great similarity of many monoclonal and conventional antibodies indicates that the cleanest of the conventional antisera are truly monospecific, and gives credence to the H-2 serology as defined by conventional antibodies. The serological analysis of monoclonal antibodies supports the true existence of private and public determinants, and reveals that the H-2 and Ia determinants are complex, even when the antibody is simple.     

Schistosoma: cross-reactivity and antigenic community among different species

It is not unusual to find common molecules among different species of the genus Schistosoma. When those molecules are antigenic, they may be used in immunodiagnosis and vaccines, but they could also be applied to taxonomic and evolutionary studies. To study cross-reactivity and antigenic community among different species of schistosomes, plasmas from laboratory animals infected with Schistosoma bovis, S. guineensis, S. rodhaini, S. haematobium, and four strains of S. mansoni were evaluated with a crude extract of adult worms of S. mansoni by Western blot. Using the multiple antigen blot assay, plasmas from these infected animals were exposed to a selected group of synthetic peptides from Sm28GST, Sm28TPI, Sm elastase, Sm97, Sm32, Sm31, and Sm Cathepsin L. The results presented herein demonstrate differential cross-reactivity and antigenic community among the Mansoni and Haematobium groups of schistosomes, which is of relevance as an additional new tool for phylogenetic studies of schistosomes as well as for diagnosis and vaccine purposes.     

Assigning alleles to different loci in amplifications of duplicated loci

Duplicated loci, for example those associated with major histocompatibility complex (MHC) genes, often have similar DNA sequences that can be coamplified with a pair of primers. This results in genotyping difficulties and inaccurate analyses. Here, we present a method to assign alleles to different loci in amplifications of duplicated loci. This method simultaneously considers several factors that may each affect correct allele assignment. These are the sharing of identical alleles among loci, null alleles, copy number variation, negative amplification, heterozygote excess or heterozygote deficiency, and linkage disequilibrium. The possible multilocus genotypes are extracted from the alleles for each individual and weighted to estimate the allele frequencies. The likelihood of an allele configuration is calculated and is optimized with a heuristic algorithm. Monte‐Carlo simulations and three empirical MHC data sets are used as examples to evaluate the efficacy of our method under different conditions. Our new software, mhc‐typer V1.1, is freely available at https://github.com/huangkang1987/mhc-typer .     

Rat kappa-chain allotypes. III. Serological and genetic analysis of RI-1b cross-reactivity in Australian Rattus

The presence of rat kappa-chain allotype specificities (RI-1a and b) has been studied in 13 subspecies of the seven native Australian species of Rattus. RI-1a reactivity was not detected among these rats. On the other hand, extensive cross-reactivity was seen with RI-1b, some sera cross-reacting totally (R. leucopus cooktownensis), some not at all (R. colletti), and the remainder showing at least two distinct levels of partial cross-reactivity, confirming the existence of multiple specificities for RI-1b. Three subspecies show polymorphism with respect to RI-1b cross-reactivity (R. sordidus, R. colletti, and R. l. leucopus) and in one case (leucopus) breeding studies have indicated that there is allelic inheritance of this trait. The segregation of RI-1b reactivity has been studied in crosses and backcrosses made between species differing in their RI-1b reactivity, and the results are consistent with the existence of codominant alleles at a single locus. The fact that these species differ extensively in their karyotype opens the door to possible chromosomal localization of this and other genetic traits.     

Binding characteristics and cross-reactivity of three different antilipid A monoclonal antibodies

A detailed characterization of binding specificity and cross-reactivity of three antilipid A murine mAb was performed. Binding characteristics of these three mAb were investigated against Ag (ReLPS, lipid A, derivatives of lipid A) in solid phase (ELISA) and in fluid phase (C consumption, inhibition studies), and upon incorporation in membranes (E: passive hemolysis assay, and liposomes: inhibition studies). Cross-reactivity with heterologous Ag was investigated in ELISA (LPS, Gram-negative bacteria) and immunoblot experiments (LPS). The binding specificity of mAb 26-5 (IgG2b), raised against synthetic lipid A, was located in the hydrophilic region of biphospholipid A and was also exposed after membrane incorporation of lipid A or after preincubation of lipid A with polymyxin B (PMX). mAb 26-20 (IgM), also raised against synthetic lipid A, showed binding specificity for the hydrophobic region of lipid A: no binding to membrane-associated lipid A could be demonstrated, and binding in ELISA could be blocked very efficiently by PMX. The reaction pattern of mAb 8-2 (IgM), raised against the heat-killed Re mutant of Salmonella typhimurium, was in part similar to that of mAb 26-20. However, inhibition of binding with PMX was less efficient and a high specificity for ReLPS, also after membrane incorporation of this Ag, was demonstrated. In contrast to mAb 26-5 and 26-20, mAb 8-2 showed extensive cross-reactivity with heterologous LPS preparations and heat-killed as well as live Gram-negative bacteria. It is concluded that each of the three mAb binds to a different antigenic epitope in lipid A and that exposure of those epitopes for antibody binding is restricted in a differential manner, depending on mode of Ag presentation. The here defined reaction patterns provide a basis for the interpretation of potential inhibitory effects on in vitro and in vivo biologic (and toxic) activities of endotoxins and Gram-negative bacteria.     

Serological detection of H-2K- and H-2D-gene products

Using the fluorescence-activated cell sorter (FACS II), we have analyzed the expression of H-2K- and H-2D-gene products on the membrane of various cellular components of the murine immune system. Using this serological technique we show a basic difference between T and B lymphocytes. Whereas all cellular components analyzed — hydrocortisone-resistant thymocytes, splenic T and B lymphocytes, macrophages and bone-marrow cells — expressed H-2K-subregion-encoded alloantigens at a high density, it seems that the high density expression of H-2D-encoded alloantigens is restricted mainly to B cells and to macrophages. Hydrocortisone-resistant thymocytes, splenic T lymphocytes and bone-marrow cells, on the other hand, showed significant expression of the H-2D alloantigens only at low membrane density. These results, then, provide evidence for the existence of an imbalance in serologically detectable expression of H-2K- and H-2D-region-gene products on the cell membrane of various cells comprising the murine immune system.Abbreviations usedin this paper DTH delayed type hypersensitivity - FCS fetal calf serum - FITC fluorescein isothiocyanate - HrT hydrocortisone-resistant thymocytes - Ig immunoglobulins P. De Baetselier is an EMBO and Euratom postdoctoral fellow     

Immunological cross-reactivity between electric-eel acetylcholinesterase and rat-tail-tendon collagen.

Immunological cross-reactivity between acetylcholinesterase from the electric organ of the electric eel and rat tail tendon collagen was examined both on the cellular and humoral levels. 1. Guinea pigs immunized with rat tail tendon collagen displayed a strong delayed-type skin reaction when tested with the elongated acetylcholinesterase preparation (i.e. 14-S + 18-S molecular forms). However, when the glubular 11-S enzyme was tested, almost no cross-reactivity was obtained. Similarly, guinea pigs immunized with 14-S + 18-S preparation exhibited skin sensitization to rat tail tendon collagen. 2. Using a radioimmunoassay, it was observed that 125I-labeled 14-S + 18-S acetylcholinesterase binds efficiently to rabbit antiserum elicited against rat tail tendon collagen, whereas 125I-labeled 11-S enzyme does not bind at all to this antiserum. Similar results were obtained by passive hemagglutination assay. The experiments suggest that 14-S + 18-S acetylcholinesterase, but not 11-S enzyme, which is devoid of the tail structure, has antigenic determinants in common with collagen from rat tail tendon.