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 . The genetic control of antibody production following immunization with cryptococcal polysaccharide might explain the high variability of humoral responses during cryptococcosis.     

Genetic control of the humoral response to an H-2 public specificity.

The humoral response of mice to an H-2 public specificity, termed H-2. '28' was found to be under genetic control. The genes determining this specificity were mapped to both the H-2K and H-2D regions, suggesting possible structural homologies between the products determined by these two regions. Genetic analyses indicated that a single non-H-2-linked gene regulates the anti-H-2. '28' response. In a backcross study, no linkage was detected between this putative H-2. '28' Ir gene and either the V H region or the Ly-2 locus to which the K-light chain locus is linked. Thus, a regulatory rather than a structural genetic locus seems a more likely basis for differences in response to this antigen. Our data further indicate that control of the humoral response to H-2. '28' is determinant specific since responses of the same backcross mice to other K and D alloantigens were not found to be subject to the same control.     

Genetic control of the immune response of mice to highly dinitrophenylated human gamma-globulin (DNP56HGG)

The immune response to highly dinitrophenylated human gamma-globulin (DNP56HGG) was tested in inbred strains of mice. Significant differences in the anti-DNP response among inbred strains were found, including the magnitude of serum antibody and the location of plaque-forming cells (spleen or lymph nodes). The strain differences persisted when the dose and adjuvant were changed. The genetic control of the anti-DNP response to DNP56HGG was investigated. The analysis of the response of congenic and F1 hybrid mice to DNP56HGG suggests that at least two genes are involved in the control of the anti-DNP response. The two genes are demonstrated by complementation in the F1 generation, and show no correlation with H-2 haplotype or IgG2a allotype. A third gene may be implicated by differences in response observed between male and female mice.     

Glu742 substitution to Lys enhances the EDTA tolerance ofEscherichia coli PQQ glucose dehydrogenase

Summary Based on homology analysis of the PQQ (pyrroloquinoline quinone) glucose dehydrogenase (PQQGDH) gene fromEscherichia coli andAcinetobacter calcoaceticus, Glu742 was substituted to Lys by site directed mutagenesis of theE. coli PQQGDH gene (gcd). The mutant enzyme, E742K showed higher tolerance towards EDTA inactivation than wild type PQQGDH. This is the first mutagenesis study of putative a PQQ binding site in PQQ enzyme.     

Multigenic control of immune responses of inbred mice against the terpolymers poly(Glu57Lys38Ala5) and poly(Glu54Lys36Ala10) and linkage withH-2 haplotype

Results of immunizations of recombinant inbred and congenic strains of mice with the random polymers poly(glu⁵⁷ lys³⁸ala⁵) or GLA⁵ and poly(glu⁵⁴lys³⁶ala¹⁰) or GLA¹⁰ indicate that there is an association of the responsiveness with theH-2 haplotype. Although the C57BL/6J mice (H-2 ^b haplotype) are “non responders”, the C57BL/6By originally derived from mice of the same haplotype are responders. The immune response pattern of recombinant strains carrying haplotypes derived by crossing over within theH-2 complex indicate that the responsiveness is under control of anIr gene which maps to the left of theIB subregion. Studies with the backcross mice indicated multigenic control of the responsiveness, with one locus beingH-2 linked and another locus segregating independently ofH-2.     

Two novel gene mutations (Glu174→Lys,Phe383→Tyr) causing the “hepatic” form of carnitine palmitoyltransferase II deficiency

Carnitine palmitoyltransferase II (CPT II) deficiency has two different clinical forms, one with “hepatic” and the other with “muscular” symptoms. We studied the molecular basis of the “hepatic” form in two Japanese siblings. Their CPT II activity in lymphoblasts was reduced to 3% of the level observed in normal controls. cDNA analysis showed that the proband was a compound heterozygote. One allele carried a new mutation, G621→A (Glu174→Lys). The other carried three single-base substitutions; a new mutation, T1249→A (Phe383→Tyr), and two previously reported polymorphisms. The brother had the same four substitutions. Neither of the two new mutations in this study was detected in the 60 alleles of 30 Japanese control subjects. Secondary structure prediction analysis of the mutated CPT II protein was different from that of the normal protein. We concluded that these mutations caused the “hepatic” form of CPT II deficiency in the probands. Received: 16 October 1995     

Genetic control of the immune response to staphylococcal nuclease

Summary Antibody responses of inbred strains of mice to staphylococcal nuclease were studied by isoelectric focusing in polyacrylamide gels followed by in situ labeling of focused antibodies with radioactive antigen. All A/J mice examined produced antinuclease antibodies of limited heterogeneity, and although there was individual variation in the focusing patterns observed, a characteristic spectrotype produced by all of the animals could be discerned. In order to determine the possible relationship between this characteristic spectrotype and the cross-reactive idiotypes of A/J antinuclease antibodies previously described (7), focused antibodies were also examined with a radioactively labeled pig anti-(A/J antinuclease) anti-idiotypic antibody preparation. Using this reagent, similar spectrotypes to those observed for antigen binding were seen in all of the individual A/J sera, suggesting that cross-reactive idiotype expression is a reflection of the characteristic spectrotypes observed. The same labeled anti-idiotypic reagent revealed characteristic but different spectrotypes when used to develop focused antinuclease antibodies from individual mice of other strains, suggesting that the use of similar variable region structures may be a common feature of the antinuclease response in mice of different allotypes. These studies thus provide a structural basis for the genetics of idiotype expression defined previously by serologic analysis.     

Antigen-Specific T-cell factors in the immune response to poly(Tyr,Glu)-poly(Pro)-poly(Lys)

The production by T cells of an antigen-specific factor capable of replacing the T-cell function in specific antibody formation was used as a tool for studying the cellular aspects of the genetic control of immune responses. The ability of different T-cell populations to produce a cooperative signal and the ability of B-cell populations to react to this signal were studied in different mouse strains. The antigen used was the synthetic polypeptide poly(LTyr,LGlu)-poly-(LPro) —poly(lXys), (T,G)-Pro -L, the response to which was found not to beH-2-linked. It was found that the SWR strain of mice, a low responder to (T,G)-Pro -L, is not capable of producing a T-cell factor specific to this antigen, but its B cells react normally to an active factor produced in a high responder strain. In the DBA/1 strain, also a low responder to (T,G)-Pro -L, the bone marrow cells are not able to cooperate with an active T-cell factor to produce anti-(T,G)-Pro —L-specific antibodies, while their T cells do produce a (T,G)-Pro -L-specific factor. The SWR (low responder) B cells can be triggered by DBA/1 (low responder) T cells factor specific to (T,G)-Pro —L to produce an antibody response to this immunogen. These results suggest that the immune response to (T,G)-Pro -L is controlled by two genes which are expressed in different lymphocyte populations.     

Genetic control of the immune response

(I) The influence of the dose of antigen on the amount of antibodies produced was studied in two inbred strains of mice that were different with respect to the ability to produce antibodies top-aminobenzoic acid, i.e. well responding strain B10.LP and poorly responding CBA/J strain. Similar dependence between the dose of antigen and the antibody titre was demonstrated in both strains. (2) It was found that the type of reaction to the antigenic determinant (i.e. hapten) appeared to be a constant property of the inbred strain and that it did not change during the long period of the immunological maturity of the organism. (3) Antibodies of 19S type (2-mercaptoethanol sensitive) were formed in sera of both inbred strains, particularly in strain B10.LP, even after the third adjuvant immunization. Antibodies of 7S type appeared to be partially 2-mercaptoethanol sensitive, however, the major part was resistant to this agent. No 7S, 2-mercaptoethanol resistant antibodies were found in sera of the poorly responding strain CBA/J.     

Genetic control of the immune response

(1) Inbred strains of mice when immunized withp-aminobenzoic acid and sulphanilic acid bound by diazo-linkage to the same protein carrier molecule (bovine gamma globulin) differ in their ability to respond by antibody formation. The strains A and CBA/J form only low levels of antibodies to the haptens after immunization; in strains ScSN and B10.LP the same high titers of antibodies to both haptens were found under these conditions. The strain B10.D₂ forms antibodies well to sulphanilic acid, antip-aminobenzoic acid antibodies are formed only in very low quantity. (2) Individual mice of an inbred strain form a homogeneous population in respect of their capability or inability to form a particular antihapten antibody. The individual titers in a given inbred strain vary only slightly. On the contrary the noninbred strain H shows great variability both in quantity and quality of the immune response to the haptens. (3) The crossing of good and poor anti-hapten antibody producing strains shows in F₁; F₂ and B₁ generation, that the ability to produce antibodies againstp-aminobenzoic and sulphanilic acid depends on the genotype of a given individual. The ability to respond is transmitted to the offspring as a dominant trait. (4) There is no difference in the response to the haptens between males and females of the same strain. (5) The antibodies to the haptens in different strains of mice differ in the ratio of 2-mercaptoethanol sensitive and 2-mercaptoethanol resistant antibody. Dedicated to Academician Ivan Málek on the occasion of his 60th birthday     

Genetic control of the immune response

The participation of cells from bone marrow and thymus in the antibody response to haptens was studied in two inbred strains of mice: poorly (CBA/J) and well (B10.LP) responding to immunization. The cell transfer experiments showed that the genetic regulation of the antihapten response under study, was bound directly to lymphatic cells of the immune system. For transfer of the good response it was essential that the thymus and bone marrow cell mixture contained bone marrow cells from well responding donors. Furthermore, the effect of endotoxin on antibody formation was studied in both well and poorly responding strains. It was found that endotoxin enhanced the antibody formation in both strains similarly so that the finεl differences between the levels of antibodies formed in both strains remained unchang d. Finally, it was demonstrated that endotoxin played the most important role in the primary stimulation, where the highest increase of the antibody response was obtained.     

Genetic control of the murine immune response to cholera toxin

This study was undertaken to determine whether previously noted differences in the immune response of inbred strains of mice to cholera toxin (CT) might be under immune response gene control. A series of inbred, congenic, and intra-H-2I region recombinant mouse strains were tested for responsiveness to CT after i.p. immunization with 0.1 micrograms CT in alum. Samples of plasma were collected at intervals before and after priming and boosting. IgG and IgA anti-CT were measured by ELISA. In three different sets of congenic strains, the level of IgG anti-CT clearly depended on the H-2 haplotype of the strain rather than on any background or Igh genes. Strains with the H-2b and H-2q haplotypes were high responders, and strains with the H-2k, H-2s and H-2d haplotypes were low responders. Within the H-2 complex, the IgG anti-CT response was mapped to the I-A subregion with the use of congenic intra-H-2I region recombinant strains. In contrast to these results with IgG anti-CT, plasma IgA anti-CT levels were uniformly low and indeterminate. We conclude that the murine IgG anti-CT response is controlled by a locus within the I-A subregion of H-2--a remarkable finding, considering the known abilities of this toxin to bind to and to directly stimulate lymphocytes.