Genes on different chromosomes influence the antibody response to bacterial antigens

Genetic variation influences the B-cell response to immunization with a pneumococcal polysaccharide conjugate vaccine

CBA/J mice immunized with pneumococcal 23F-CRM(197) vaccine produce significantly lower titers of 23F-specific antibodies and fewer 23F-specific antibody-secreting cells (ASC) than did BALB/c or (CBA/J x BALB/c)F(1) (CCBAF(1)) mice. The reduced 23F-specific titers of CBA/J versus BALB/c or CCBAF(1) mice are presumably related to lower frequencies of 23F-specific ASC influenced by genetic variation.

Antibody responses to ganglio-series gangliosides in different strains of inbred mice

We studied antibody responses after immunization with ganglio-series gangliosides against 10 strains of inbred mice, including Balb/c, C57BL/6, A/J, C3H/HeN, C3H/HeJ, CBA/N, AKR/N, NZB/N, DBA/2 and nu/nu Balb/c. Twelve gangliosides having NeuAc as their sialic acid moiety (GM4, GM3, GM2, GM1, GD3, O-Ac-GD3, GD2, GD1a, GD1b, GT1a, GT1b and GQ1b), four gangliosides having NeuGc (GM3, GM2, GM1 and GD3) and four asialo-gangliosides (GA4, GA3, GA2 and GA1) were injected intravenously adsorbed to Salmonella minnesota. The antibody titers of the mice sera were determined by an enzyme-linked immunosorbent assay and an immune adherence assay. Antibody responses were found to depend not only on the ganglioside used as an immunogen but also on the mouse strain. Gangliosides having a trisaccharide sequence (NeuAc alpha 2----8NeuAc alpha 2----3Gal-) such as GD3, GD2, GD1b, GT1a and GQ1b, in particular O-Ac-GD3, induced high-titer antibody responses, whereas those having a disaccharide sequence (NeuAc alpha 2----3Gal-) such as GM4, GM3, GM2, GM1, GD1a and GT1b induced low-titer antibody responses. On the other hand, gangliosides with NeuGc developed minimum titers. In contrast, asialogangliosides induced much higher responses than the corresponding gangliosides. The differences in ceramide portions of these gangliosides did not appear to be involved in inducing antibody responses. Mice could be divided into three groups according to the magnitude of their antibody responses: Group 1, those that produce the highest antibody responses (C3H/HeN and A/J); Group 2, those that demonstrate moderate antibody titers (Balb/c, C57BL/6, DBA/2 and nu/nu Balb/c); and Group 3, those that make minimum responses (AKR/N, C3H/HeJ, CBA/N and NZB/N). The pattern of reactivity to the various gangliosides was similar in all the strains tested.

Genetic control of serum antibody responses of inbred mice to type 1 and type 2 fimbriae from Actinomyces viscosus T14V

Antibodies reactive with type 1 and type 2 fimbriae from Actinomyces viscosus T14V specifically inhibit the adherence of A. viscosus T14V to salivary pellicle-coated tooth surfaces and other bacteria, and these antibodies are thought to modulate colonization by this microorganism. These studies were done to determine whether previously noted differences in the antibody responses of inbred mice to type 1 and type 2 fimbriae might be under genetic control. The serum immunoglobulin G (IgG) and IgM antibody responses of inbred, F1 hybrid, and H-2 congenic mice, immunized with A. viscosus T14V cells, were analyzed by enzyme-linked immunosorbent assays for antibodies reactive with A. viscosus T14V whole-cell type 1 and type 2 fimbriae. The results confirmed earlier findings and indicated striking variations in the amounts of IgG anti-type 1 (23-fold) and anti-type 2 (48-fold) fimbria antibodies elicited. The responses of the 17 inbred strains tested showed a relatively continuous distribution from high to low, as well as marked differences in the responses of H-2 and Igh-C identical strain pairs. An analysis of the responses of F1 hybrid and H-2 congenic mice indicated dominance of the low-responder gene(s) and control by H-2-linked genes. Antisera from two high-responder strains inhibited in vitro bacterial adherence to a much greater degree than antisera from a low-responding strain. These data suggest polygenic control of the magnitude of the IgG anti-type 1 and anti-type 2 fimbria antibody responses by H-2-linked genes as well as background genes not associated with H-2 or Igh-C loci.

Genetic control of the humoral response to cryptococcal capsular polysaccharide in mice

Cryptococcus neoformans is responsible for opportunistic infections in patients with cellular immune defects. However, C. neoformans-specific capsular polysaccharide antibodies have been shown to participate in host defenses during cryptococcosis. We investigated the humoral response after primary immunization in various inbred strains of mice and the genetic control. Our data strengthen the arguments for the T-independent type-2 nature of cryptococcal antigen, since CBA/N mice were unable to produce specific antibodies. They show that the influence of the genetic background is predominant for the good response with at least four independent autosomal genes governing this response, including an Igh control as reported for other polysaccharides. Immunization of intra-H-2 recombinant mice on a B10 background allowed us to identify a major histocompatibility complex control located in the subregion E alpha. The genetic control of antibody production following immunization with cryptococcal polysaccharide might explain the high variability of humoral responses during cryptococcosis.

Inbred mice infected with Plasmodium yoelii differ in their antimalarial immunoglobulin isotype response

Antibodies are known to be important in mediating malarial immunity, but the influence of the various immunoglobulin isotypes on parasite elimination is unclear. The purpose of this study was to provide basic information on the induction of isotype expression in genetically different mice during primary malaria. Parasitaemias and the serum antimalarial IgM, IgG1, IgG2, IgG3 and IgA antibody titres measured in a radioimmunoassay were followed in outbred and 11 inbred strains of mice infected with 17XNL Plasmodium yoelii. Severity of infection, as judged by length of infection, peak parasitaemias and death, was found to differ between the strains. All strains developed rapid IgM responses, but only 3/11 inbred strains produced significant antimalarial IgG1 levels during primary infection. All strains produced an IgG2 response, which developed slightly more quickly in strains with the least severe courses of malaria. A large variation in the IgG3 response was noted between strains. In general, IgG3 antibodies were the first IgG-isotype to appear in serum. They were detected as early as day 8 in strains that developed mild infections but were not present until around day 20 in strains with the most severe cases of malaria. Only one strain produced detectable antimalarial IgA antibodies. These results show that different patterns of isotype expression are induced in inbred strains of mice during primary P. yoelii infection.

Murine primary in vivo response to TNP-Ficoll: multigenic control involving H-2

Since the primary PFC response to TNP-Ficoll, a thymus-independent type 2 antigen, displays an important variability in vivo among diverse inbred mouse strains, we used, in the present report, H-2 congenic strains possessing different genetic backgrounds to show that the amplitude of this response is governed by MHC genes, with one regulating locus situated in or near the centromeric part of the I-A subregion. In addition, this H-2 control was largely modulated by gene(s) located outside MHC and IgH haplotypes, as evidenced by the response of recombinant inbred strains (BXH) between the high responder C3H/HeJ and the low responder C57BL/6J. Our results are discussed in terms of humoral regulations and the requirement for self-recognition in cellular interactions which lead to activation of B lymphocytes in the in vivo primary response towards TI-2 antigens.