Broad phylogenetic expression of heavy-chain determinants detected by rabbit antisera to VHa allotypes

Immunoglobulin molecules from diverse vertebrate species were examined, using an enzyme-linked immunosorbent assay (ELISA), for the expression of determinants detectable by rabbit antisera to VHa allotypes. The data indicate that immunoglobulins of elasmobranchs, teleosts, amphibians and birds express determinants cross-reactive with those specified by the a1, a2 and a3 alleles in the domestic rabbit. We localize VHa cross-reactive specificity to the denatured heavy chain of a primitive vertebrate, the Galapagos shark (Carcharhinus galapagensis). Furthermore, the N-terminal amino acid sequence of the shark heavy chain shows significant homology with rabbit heavy chains of known VHa type at positions where allotype-correlated differences have been implicated. VHa-related determinants are shared by immunoglobulins of a wide range of vertebrates from sharks to man and thus seem to be epitopes which have been conserved during vertebrate evolution. The determinants detected on immunoglobulins of lower vertebrates by rabbit anti-VHa allotype sera most probably are VH-subgroup rather than allotypic markers. Their distribution demonstrates a strong phylogenetic conservation of VH-regions.     

Genetic control of allogeneic interactions in the guinea-pig. V. Evidence for a dissociation between genes coding for A GPLA-B region-controlled determinant and genes coding for MLC suppressor cells.

The genetic basis of guinea-pig leucocyte antigen (GPLA)-B.2-associated unresponsiveness in the guinea-pig mixed leucocyte culture (MLC) was investigated using fibroblasts as stimulating cells. Guinea-pig foetal fibroblasts bearing the B.2 specificity can stimulate allogeneic but not syngeneic lymph node lymphocytes, whereas B.2-bearing peritoneal exudate cells (PEC) induce specific unresponsiveness. The inhibition of the mixed leucocyte-fibroblast reaction is seen only when the alloantisera are directed against the stimulatory fibroblast rather than the responding lymph node lymphocytes. Furthermore, B.2-bearing fibroblasts, in contrast to B.2-bearing PEC, fail to elaborate MLC-suppressor factor. It appears therefore, that in guinea-pig fibroblasts there is an apparent dissociation between major histocompatibility complex (MHC; in the region of the B locus) genes and the gene(s) coding for B.2-associated MLC suppressor cells and factor(s).     

Evidence for a susceptibility locus on chromosome 6q influencing phonological coding dyslexia

A linkage study of 96 dyslexia families containing at least two affected siblings (totaling 877 individuals) has found evidence for a dyslexia susceptibility gene on chromosome 6q11.2-q12 (assigned the name DYX4). Using a qualitative phonological coding dyslexia (PCD) phenotype (affected, unaffected, or uncertain diagnoses), two-point parametric analyses found highly suggestive evidence for linkage between PCD and markers D6S254, D6S965, D6S280, and D6S251 (LOD(max) scores = 2.4 to 2.8) across an 11 cM region. Multipoint parametric analysis supported linkage of PCD to this region (peak HLOD = 1.6), as did multipoint nonparametric linkage analysis (P = 0.012). Quantitative trait linkage analyses of four reading measures (phonological awareness, phonological coding, spelling, and rapid automatized naming speed) also provided evidence for a dyslexia susceptibility locus on chromosome 6q. Using a variance-component approach, analysis of phonological coding and spelling measures resulted in peak LOD scores at D6S965 of 2.1 and 3.3, respectively, under 2 degrees of freedom. Furthermore, multipoint nonparametric quantitative trait sibpair analyses suggested linkage between the 6q region and phonological awareness, phonological coding, and spelling (P = 0.018, 0.017, 0.0005, respectively, for unweighted sibpairs < 18 years of age). Although conventional significance thresholds were not reached in the linkage analyses, the chromosome 6q11.2-q12 region clearly warrants investigation in other dyslexia family samples to attempt replication and confirmation of a dyslexia susceptibility gene in this region.     

Evolutionary dynamics of the human immunoglobulin kappa locus and the germline repertoire of the Vkappa genes

We have determined the entire nucleotide sequence of the human immunoglobulin kappa locus, comprising a total of 1,010,706 nucleotides. The 76 Vkappa genes found by a hybridization-based approach and their classification in 7 families were confirmed. A Vkappa orphon located near the locus was also sequenced. In addition, we identified 55 novel Vkappa relics and truncated pseudogenes, which establish 5 new families. Among these 132 Vkappa genes, 46 have open reading frames. According to the databases and the literature, 32 unique Vkappa genes and 5 identical gene pairs form VJ-joints, 27 unique genes and 4 gene pairs are transcribed, and 25 unique genes and 4 gene pairs produce functional proteins. The Vkappa gene locus contains a 360-kb inverted duplication, which harbors 118 Vkappa genes. A comparison of the duplicated Vkappa genes suggests positive selection on the complementarity-determining regions of the duplicated genes by point mutations. The entire duplication unit was divided into 13 blocks, each of which has its distinct nucleotide sequence identity to its duplication counterpart (98.1 - 99.9 %). An inversion-mediated mechanism is suggested to generate the high-homology blocks. Based on the homology blocks and the mutation rates, the inverted duplication is assumed to have taken place approximately 5 million years ago. An orphon Vkappa gene near the kappa locus and a cluster of five Vkappa orphons on chromosome 22 have no counterparts within the kappa locus. This suggests possible mechanisms of the transposition of orphon Vkappa genes.     

The quaternary Gs3 and Gs7 allotypes of the rabbit: generation of the determinants by interspecies molecular hybridization

A number of allotypic markers of the rabbit immunoglobulins are present only on intact immunoglobulin molecules and not on the isolated heavy or light chains. Some of these markers, although determined by the kappa light chain, are limited to a single heavy chain class of Ig. They can be generated by in vitro hybridization of the kappa light chain with the appropriate heavy chain. The quaternary IgG allotypic determinants Gs3 and Gs7 which are determined respectively by the b4.1 and b4.2 allelic variants of the kappa b4 light chain can be generated not only by in vitro hybridization of these light chains with a rabbit gamma chain, but also to a certain extent by their hybridization to gamma chains derived from other species.     

Cosuppression of latent and nominal allotypes in individual rabbit lymphocytes.

Endogenous synthesis of latent and nominal allotype was observed in vitro in rabbit peripheral blood lymphocytes (PBL). PBL from rabbits displaying the nominal b4 specificity, as well as the latent b5 and b6 either on the cell surface or in the serum or both, were treated with pronase to remove surface latent and nominal allotypes and cultured in serum-free medium to regenerate the nominal and latent markers. Rosette formation using the mixed anti-globulin assay demonstrated that the nominal b4 and latent b5 and b6 specificities were displayed in the same cell. Cells were seen bearing the b4 + b5, b4 + b6, or b4 + b5 + b6, as double or triple expressors. No latent allotype-bearing cells were detectable in the absence of the nominal allotype. In vitro suppression of nominal surface b4 with anti-b4 antibodies resulted in the cosuppression of the latent b5 and b6. In contrast, in vitro suppression of latent b5 and b6 with anti-b5 and anti-b6 antibodies, respectively, did not cause the cosuppression of the nominal b4 allotype. Cosuppression of latent and nominal markers in the same cell confirms that the biosynthetic machinery for latent and nominal allotypes lies within the same cell.     

Evidence for a fourth locus in Usher syndrome type I.

Usher syndrome type I (US1) is an autosomal recessive condition in which three different genes have been already localised (USH1A, USH1B, and USH1C on chromosomes 14q32, 11q13, and 11p15 respectively). The genetic heterogeneity of US1 has been confirmed in a previous study by linkage analysis of 20 French pedigrees. Here, we report the genetic exclusion of the three previously reported loci in two large multiplex families of Moroccan and Pakistani origin, suggesting the existence of at least a fourth locus in Usher syndrome type I.     

Expression of rabbit Ig allotypes in litters of mothers immunized against a paternal allotype.

Sera of successive littermates of mothers producing anti-allotype antibodies (Ab) were analysed for altered a locus or b locus allotype expression. We measured the allotype concentration in sera of 66 individuals (17 litters) of seven mothers producing anti-a1 Ab, and 63 individuals (15 litters) of seven mothers producing anti-b4 Ab, in an enzyme-linked immunosorbent assay (ELISA). We confirmed that the ability to induce allotype suppression in utero increases with the number of antigen boosts applied to the mother, even though the Ab titre in the maternal serum may be decreased. All individuals of a litter expressed the allotype in about equal concentration. This contrasts the results we obtained when newborn rabbits were injected with anti-allotype antiserum. Injection of the same amount of anti-allotype antiserum into nine offspring of two mothers caused allotype suppression in only five individuals, showing no effect in the others. No suppression was observed when IgG-depleted antiserum was injected into newborn rabbits. As expected, maternal antibodies to a paternal allotype do not affect the Mendelian distribution of the progeny phenotypes.     

Pathogenic germline variants in patients with features of hereditary renal cell carcinoma: Evidence for further locus heterogeneity

Inherited renal cell carcinoma (RCC) is associated with multiple familial cancer syndromes but most individuals with features of non‐syndromic inherited RCC do not harbor variants in the most commonly tested renal cancer predisposition genes (CPGs). We investigated whether undiagnosed cases might harbor mutations in CPGs that are not routinely tested for by testing 118 individuals with features suggestive of inherited RCC (family history of RCC, two or more primary RCC aged <60 years, or early onset RCC ≤46 years) for the presence of pathogenic variants in a large panel of CPGs. All individuals had been prescreened for pathogenic variants in the major RCC genes. We detected pathogenic or likely pathogenic (P/LP) variants of potential clinical relevance in 16.1% (19/118) of individuals, including P/LP variants in BRIP1 (n = 4), CHEK2 (n = 3), MITF (n = 1), and BRCA1 (n = 1). Though the power to detect rare variants was limited by sample size the frequency of truncating variants in BRIP1, 4/118, was significantly higher than in controls (P = 5.92E‐03). These findings suggest that the application of genetic testing for larger inherited cancer gene panels in patients with indicators of a potential inherited RCC can increase the diagnostic yield for P/LP variants. However, the clinical utility of such a diagnostic strategy requires validation and further evaluation and in particular, confirmation of rarer RCC genotype‐phenotype associations is required.     

Rhesus monkey (macaca mulatta) allotypes. Identification of three low density lipoprotein allotypes controlled by independent genes.

Three rhesus monkey allotypes are described, which are located on distinct low density lipoprotein molecules. These three markers have been detected using double immunodiffusion in agar. They are inherited in a simple Mendelian manner and controlled by three independent genes.     

Interactive effect of Gm allotypes and HLA-B locus antigens on the human antibody response to a bacterial antigen.

Two hundred healthy adults were immunized with 1 microgram of the bacterial antigen monomeric flagellin from Salmonella adelaide, and grouped as responders and non-responders on the basis of a rise in titre of antibody 2 weeks after immunization. Immunoglobulin allotypes G1m(a), G1m(z) and G3m(g) were more frequent among responders who made immunoglobulin (Ig)G antibody (P less than 0.02), and HLA-B12 was more frequent among responders who made IgM antibody (P less than 0.05). The mean log titre of IgG antibody was higher in females (P less than 0.001), in subjects with T1m(a), G1m(z) and G3m(g) allotypes (P less than 0.05), and in Gm heterozygotes (P less than 0.01). The mean log titre of the IgG antibody response in subjects with particular Gm phenotypes was also dependent on the HLA-B locus phenotypes HLA-B7, B8 and B12 (P less than 0.005); for example, among those with the phenotype Gm(a-x-b) subjects with HLA-B7 were low responders and those with HLA-B8 were high responders. These findings are consistent with the hypothesis that there are immune response genes within the major histocompatibility complex (MHC) which interact with Gm-linked genes in determining levels of serum antibodies of different isotypes and specificities.     

Evidence for antigenic determinants shared by the structural polypeptides of (Shope) rabbit papillomavirus and human papillomavirus type 1.

In contrast to antivirion antisera raised against (Shope) rabbit papillomavirus (RPV) and human plantar wart papillomavirus (HPV-1), sera of rabbits bearing Vx7 carcinoma, a transplantable tumor deriving from a RPV-induced papilloma, permit the detection of an antigenic relationship between these viruses. Sera containing anti-RPV antibodies were collected between the 116th and 165th transplant from 10 rabbits selected for their large intramuscular tumors of long duration or for their purposely grafted tumors (both intramuscularly and intraperitoneally). When tested by immunofluorescence using plantar wart sections, seven of these sera detected an antigen whose location corresponds to that of HPV-1 capsid antigens. The reactivity of fluorescein-conjugated IgG, obtained from the most cross-reactive serum, was abolished by incubation with alkali-disrupted HPV-1 virions but not with intact HPV-1 particles. In contrast to an anti-HPV-1 virion antiserum, this Vx7 serum reacted with the main HPV-1 structural polypeptide (MW, 54,000) after SDS disruption and iodination of HPV-1 particles, as shown by radioimmunoprecipitation. Furthermore, one of the two anti-disrupted HPV-1 virion antisera and the two-anti-HPV-1 polypeptide antisera studied reacted with RPV antigens, as shown by immunofluorescence using cottontail rabbit wart sections. Moreover, one of the cross-reactive Vx7 sera gave a precipitin line continuous to that given by an anti-HPV-1 virion antiserum when tested by immunodiffusion using HPV-1 virions as antigens. This was further observed for four of the 110 additional Vx7 sera tested. The specificity of this reaction was confirmed by immune electron microscopy experiments. Similarly, an anti-HPV-1 polypeptide antiserum reacted with RPV virions. The results indicate the existence of two kinds of antigenic determinants shared by RPV and HPV-1 structural polypeptides; some are masked in intact particles and others are located on the virion surface but in a form usually unable to elicit the formation of antibodies.     

Evidence for a role of the locus coeruleus noradrenaline system in learning

The effect of the new noradrenaline (NA) neurotoxin, DSP4, on the acquisition of one-way and two-way active avoidance responses was studied in rats. This treatment caused a marked degeneration of the iocus coeruleus NA system and markedly impaired both one- and two-way avoidance acquisition. Both effects were blocked by pretreatment with desipramine, a NA uptake blocking agent. The present findings support the hypothesis that the locus coeruleus NA system in its entire extent may play a role in aversive learning.