Surface immunoglobulins of lymphocytes in plasmacytoma. V. The effect of RNA-rich extract from mouse plasmacytoma MOPC 104E on the immune response.

BALB/c mice with the plasmacytoma MOPC 104E producing monoclonal IgM-lambda with antibody activity to alpha-1,3 dextran were found to have B lymphocytes with surface immunoglobulins with the immunochemical characteristics of 104E IgM capable of binding alpha-1,3 dextran. RNA extracted from this plasmacytoma induced the synthesis of such surface immunoglobulins on normal B lymphocytes in vitro and in vivo. Injection of 200 mug of MOPC 104E RNA into normal mice 72 hr prior to the administration of the antigen kept the immune response to dextran-S intact, but suppressed that to other antigens, such as DNP-Ficoll and LPS, T cell-independent antigens, and SRBC and BSA which are T cell-dependent. The effect of the RNA was abolished by RNase but not by pronase and DNase. RNA extracted from LPC-1 tumour (gamma2a-k without known antibody activity) significantly suppressed the immune response to dextran-S and to other antigens in normal mice. Thus, opposite effects of MOPC 104E RNA on the response to specific and non-specific antigens strengthen the hypothesis that the immune deficiency in plasmacytoma bearing mice is due to the conversion of normal surface immunoglobulin of a population of B lymphocytes to the idiotype of the respective myeloma globulin.     

Genetic polymorphism of IgG in the mink. V. Two new genetic markers of the lambda light chains of mink immunoglobulins, L4 and L5

Two new allotypes of the light (L) chains IgG, L4 and L5, were identified in the mink with dispecific antiserum produced by immunization with allogenic IgG. By means of hybrid IgG molecules and proteolytic fragments, L4 and L5 were localized on the C region of the L chain. L4 and L5 occurred frequently in the three mink populations studied and L4 and L5 are inherited independently of the known mink C gamma allotypes. L4 and L5 are encoded by closely linked genes. The antigenic specificities of L4 and L5 were not identified in the closely related Mustelidae and in the other mammalian representatives. Consequently, L4 and L5 are species specific to mink. Determination of the phenotype combinations of the five allotypes on the L chains (including the new L4 and L5) demonstrated the existence of seven combinations only with a predominance of L1,2,3; L4,5, and L1,2,3,4,5 phenotypes. Based on the results obtained, it is concluded that the mink C lambda locus has a complex organization. A model for the mink C lambda locus with at least three or possibly five linked genes is suggested.     

Marsupial immunoglobulins: the distribution and evolution of macropod IgG2, IgG1, IgM and light chain antigenic markers within the sub-class Metatheria.

The distribution within Australian and American marsupials of the heavy and light chain antigenic markers identified by antisera to purified quokka (Setonix brachyurus) immunoglobulins is described. Markers for IgM and IgG2 constant region determinants as well as for light chains were widely distributed in Australian species and were also detected in Didelphis, the American opossum, thus indicating a long-term structural conservatism of some immunoglobulins within the marsupials. More detailed analysis of the distribution of quokka IgG2 determinants by quantitative precipitation and sequential absorption procedures suggested that there had been a gradual and cumulative acquisition of these markers with time. The presence of IgG2 markers in species separated for 130 million years (quokka and opossum) suggested that IgG2 was the ancestral IgG present before the divergence of these separate lines. The origin of IgG1 remains obscure as it appears to be limited to a small group of closely related diprotodont marsupials suggesting a recent origin.     

Adjuvant effects of amorphous silica and of aluminium hydroxide on IgE and IgG1 antibody production in different inbred mouse strains

The adjuvant effects of an amorphous silica (Aerosil) and of A1(OH)3 on primary and secondary IgE and IgG1 immune responses to small doses of OA were studied comparatively in BALB/c, C57BL, DBA/1, AKR, DBA/2 and SJL inbred mouse strains. During the primary response, all mouse strains produced both IgG1 and IgE antibodies when antigen was given with A1(OH)3, whereas only DBA/1, BALB/c and DBA/2 mice produced IgG1 and/or IgE antibodies when Aerosil was used as the adjuvant. A booster effect, higher than that obtained by A1(OH)3, was induced by Aerosil in all mouse strains. The adjuvant effect of Aerosil was more selectively directed to the production of IgE antibody.     

Immunoglobulins of colostrum. V. Localization of structural differences between serum and colostral ovine and bovine IgG1 and IgG2 immunoglobulins

Studies on localization of structural differences between ovine and bovine serum and colostral IgG immunoglobulins are described. Comparison of heterogeneity, susceptibility to proteolytic enzymes, peptide maps, amino acid compositions, and antigenic properties of immunoglobulins and their Fab and Fc fragments and H and L chains showed that structural differences are localized in the Fc region. The strongest differences were found in case of IgG2. It was also shown that no Fc fragments could be obtained from bovine serm IgG2 and ovine serum and colostral IgG2 due to their susceptibility to papain and trypsin. The results obtained confirmed our suggestion that colostral IgG2 are locally synthesized in mammary glands, whereas colostral IgG1 might be a mixed population of molecules locally synthesized and transferred from the serum.     

The guinea-pig I-region. III. Distribution of Ia antigens in inbred and partially inbred strains

We have used a combined serologic and structural approach to study the distribution of I-region associated (Ia) antigens in nine strains of inbred and partially inbred guinea-pigs. All of the inbred strains studied with the exception of strain 2 animals were found to share one or more I-subregions with inbred strain 13 animals. The BIOAD, R9, OM3, and BIOAC strains have the same I-region as strain 13 animals; the B/Lac strain has two subregions in common with strain 13, while the BIOB strain has a single subregion in common with strain 13. The availability of a number of different guinea-pig strains with well-characterized major histocompatibility complexes should facilitate the continuing use of this species in studies of immunogenetics, transplantation, and tumour immunology.     

Onset of T-cell receptor Vbeta8.1 and Dbeta2.1 V(D)J recombination during thymus development of inbred mouse strains.

The assembling of T-cell receptor (TCR alpha/beta and gamma/delta) genes depends on the V(D)J recombination occurring in early thymocytes during thymus ontogeny. The V(D)J recombination reaction is directed by a recombinase complex from the RAG-1 and RAG-2 genes, and is modulated by several other gene products. Due to the essential role of the TCRbeta in thymocyte differentiation, it is important to define with precision the temporal emergence of the TCRbeta recombination in normal non-manipulated mouse strains. We analysed the onset of V(D)J recombination between TCRVbeta8.1 and Jbeta2.1 gene segments during fetal development of the thymus in three non-manipulated inbred strains of mice; BALB-c, C57BL/6 and CBA. We show that the emergence of the V(D)J recombination at the TCRbeta locus differs among strains, suggesting an in vivo role of the different genetic backgrounds in driving gene rearrangements.     

Antigenic epitopes of NEF proteins from different HIV-1 strains as recognized by sera from patients with manifest and latent HIV infection.

Human immunodeficiency virus (HIV) infection that generally causes a strong antibody response toward HIV may sometimes occur in a latent form, characterized by seronegativity in assays based on structural HIV proteins. Latently infected individuals, however, often have an antibody response against the nonstructural regulatory HIV-1 protein NEF, a factor implicated in down-regulation of viral expression. In order to define the specificity of NEF antibodies, we looked for antibody response against more than 600 overlapping nonapeptides representing the total NEF sequence of three different HIV-1 isolates BRU, SF2, and MAL. Nine distinct homologous antigenic epitopes were recognized by sera from seropositive HIV-1-infected individuals by the peptide ELISA. We further demonstrated that sera from "at risk" individuals, with no antibodies to HIV structural proteins but reacting with the recombinant NEF protein in Western blot, recognize the same epitopes. Immunological assays based on the defined NEF epitopes can therefore be used to diagnose early or latent HIV Infection.     

Susceptibility of inbred and outbred mouse strains to Sendai virus and prevalence of infection in laboratory rodents.

Sendai virus is one of the more prevalent and serious virus infections of rodents. Infection was found in 66% of the mouse, 63% of the rat, 83% of the hamster, and 44% of the guinea pig colonies examined. Twenty-four inbred and outbred strains of mice were tested for their sensitivity to lethal Sendai virus infection. The 129/J mice tested were approximately 25,000-fold more sensitive than SJL/J mice; however, both mouse strains were similarly permissive in support of viral replication in their lung tissues. Histopathological studies revealed that whereas lesions in both sensitive and resistant mice were qualitatively similar, the lesions in the more sensitive 129/J mice appeared earlier, were much more extensive, and persisted longer than in the resistant SJL/J mice. These results suggest that the observed variance in sensitivity is not the result of a genetic restriction on virus infection and replication but rather is the result of a physiological factor(s) possibly related to some aberration of strain difference in the humoral or cell-mediated immune response.     

The midbrain dopaminergic system: anatomy and genetic variation in dopamine neuron number of inbred mouse strains

The mesotelencephalic dopamine system is genetically variable and affects motor behavior, motivation, and learning. Here we examine the genetic variation of mesencephalic DA neuron number in a quasi-congenic RQI mouse strain and its background partner and in a recombinant inbred strain with different levels of mesencephalic tyrosine hydroxylase activity (TH/MES). We used B6.Cb4i5-6/Vad, C57BL/6By, and CXBI, which are known to express high, intermediate, and low levels of TH/MES, respectively. Unbiased stereological sampling with optical disector counting methods were employed to estimate the number of TH-positive neurons in the A8-A9-A10 cell groups. Morphometric studies on the mesencephalic dopamine cell groups indicated that male mice of the B6.Cb4i5-6/Vad strain were endowed with a significantly lower number of TH-positive cells than CXBI mice. In all strains studied, the right retrorubral field (A8 area) had a higher number of dopamine neurons compared to the left A8 area. The results suggest an inverse relationship between TH/MES and number of dopamine neurons in the A9-A10 cell groups and significant lateral asymmetry in the A8 cell group. A detailed anatomical atlas of the mesencephalic A8-A9-A10 dopaminergic cell groups in the mouse is also presented to facilitate the assignment of TH-positive neurons to specific cell groups.     

The idiotypy of the MOPC 173 (IgG2a) mouse myeloma protein: characterization of syngeneic, allogeneic and xenogeneic anti-idiotypic antibodies. Contribution of the H and L chains to the idiotypic determinants.

Anti-idiotypic antibodies were raised against the mouse (γ_2a, κ) myeloma protein MOPC 173 in syngeneic, allogeneic and xenogeneic conditions. Syngeneic immunization resulted in individual hemagglutination titers ranging from 1:40 to 1:160000 with about 30% of nonresponders, whereas upon allogeneic immunization (in A/J mice) almost all animals responded, with titers ranging from 1:1250 to 1:320000. Anti-idiotypic antisera were also obtained in the rabbit. Inhibition of a radioimmunoassay using ¹²⁵I-labeled MOPC 173 Fab fragments as the reference antigen indicated that the native Ig and the Fab competed on a similar molar basis. No inhibition was observed with the Fc or with other mouse monoclonal Ig, of the same or different classes or subclasses. Standard BALB/c serum did not inhibit either. Whatever the anti-idiotypic antiserum used, idiotypic determinants were not found on isolated heavy (H) and light (L) chains provided they were carefully purified. Reoccurrence of idiotypic determinants was obtained in high yield whenever Ig molecules were reformed from the homologous H and L chains, whereas no potentiation of the low inhibition of isolated chains was observed when hybrid molecules were formed using heterologous complementary chains isolated from the MOPC 21A (γl, ?) or the LPC 1 (γ_2a, ?) protein. These results suggest that MOPC 173 idiotypic determinants rely on the specific H-L interaction and that they must be largely conformational in nature. Heterogeneity of the anti-idiotypic antibodies was analyzed by isoelectric focusing. A major pattern was observed for the A/J antisera, whereas, in the case of BALB/c, expression of a few clones, characteristic of each “high responder” animal, was strongly suggested, superimposed to faint production of antibodies by clones that were common to all mice.     

Resistance ranking of some common inbred mouse strains to Mycobacterium tuberculosis and relationship to major histocompatibility complex haplotype and Nramp1 genotype.

Six common inbred strains of mice and their F1 hybrids were examined for resistance to infection with the H37Rv strain of Mycobacterium tuberculosis. According to survival times after inoculation of 10(5) CFU intravenously (i.v.), the mice could be classified as being either highly susceptible (CBA, DBA/2, C3H, 129/SvJ) or highly resistant (BALB/c and C57BL/6). F1 hybrids of susceptible and resistant strains were resistant. Although an examination of a limited number of H-2 congenic strains showed that the H-2k haplotype could confer susceptibility on a resistant strain, it was evident that non-major histocompatibility complex (MHC) genes were much more important. Resistant strains all possessed the susceptibility allele of the anti-microbial resistance gene, Nramp1. Results obtained with selected strains infected with 10(2) CFU of M. tuberculosis by aerosol agreed with the results obtained with mice infected i.v. The size of the bacterial inoculum was important in distinguishing between resistant and susceptible strains, in that a 10(7) inoculum overcame the resistance advantage of one strain over another.     

Role of the host in pathogenesis of Helicobacter-associated gastritis: H. felis infection of inbred and congenic mouse strains.

In humans, Helicobacter pylori establishes a chronic infection which can result in various degrees of gastric inflammation, peptic ulcer disease, and a predisposition to gastric cancer. It has been suggested that bacterial virulence factors such as the vacuolating toxin (VacA) and the cytotoxin-associated gene product (CagA) may play a major role in determining the clinical outcome of Helicobacter infections. The role of host responses in these varied outcomes has received little attention. Helicobacter felis, which does not express CagA or VacA, causes chronic infection and inflammation in a well-characterized mouse model. We have used this model to evaluate the role of host responses in Helicobacter infections. BALB/c, C3H, and C57BL/6 mice were orally infected with a single strain of H. felis, and 2 and 11 weeks after infection, the mice were sacrificed and evaluated histologically for magnitude of H. felis infection. Intensity and extent of inflammation, and cellular composition of the inflammatory infiltrate. All three strains of mice demonstrated comparable levels of infection at 11 weeks, but the pattern and intensity of inflammation varied from minimal in BALB/c mice to severe in C57BL/6 mice. Gastric epithelial erosions were noted in C3H mice, and mucous cell hyperplasia was observed in C3H and C57BL/6 mice. Abundant mucosal mast cells were observed in the gastric tissues of all three mouse strains. Studies using major histocompatibility complex (MHC)-congenic mice revealed probable contributions by both MHC and non-MHC genes to Helicobacter-induced inflammation. Thus, large variations in the severity of disease were observed after infection of different inbred strains and congenic mice with a single isolate of H. felis. These results demonstrate the importance of the host response in disease outcome following gastric Helicobacter infection.     

The same few V genes account for a majority of oxazolone antibodies in most mouse strains.

The early primary anti-phenyloxazolone antibodies of 12 mouse strains were studied by determining proportions of two defined subsets id495 (the classical phOx idiotype) and id350. Id495-positive antibodies bear an H chain encoded by VHOx1 gene (family Q52) and an L chain usually coded for by VKOx1 but occasionally by other VK genes. Id350-positive antibodies are encoded by a VK gene VK45.1, and usually by a VH gene of the S107 family. All 12 strains (representing nine H-chain and four kappa-chain haplotypes) produced id350-positive anti-phOx antibodies. While id495 is the predominant major subset in the BALB/c response (originally studied), id350 seems to be the predominant subset of early anti-phOx antibodies in the mouse species. The combined proportion of the two subsets varied from ca. 50 to almost 100% of the total in all strains except C57BL.     

Quantitative genetic variation in the skeleton of the mouse: II. Description of variation within and between inbred strains

Variation in the skeletons of over 400 male and female mice from 12 genotypes was investigated by using multivariate statistical methods. A series of discriminant functions explains the differences in the shape of six bones: mandible, os coxae, femur, tibia-fibula, scapula, and humerus. The anatomical features of bone shape described by these functions are summarized together with illustrations of the typical shapes of each bone from the 12 genotypes. Variability within genotypes was investigated by using the Mahalanobis D² distance—a measure of the difference between two points representing multivariate data—from the group mean. A series of variants were detected ranging from grossly abnormal bones to bones showing subtle differences localized to specific regions. Examples of the variants found are illustrated.     

Genetic and sex-linked factors influencing hbs antigen clearance 1. nonimmune clearance in inbred strains of mice

Differences in the clearance values of polyvinylpyrrolidonc (K_PVP) and HBs antigen (K_HBs) were seen in several strains of inbred mice. In addition, in all strains studied K_HBs was greater in females than in males, while K_PVP was not significantly different in the two sexes. In the strain with the lowest K_HBs values, the incidence of HBs antibody formation was lower than in the other strains. These data indicate that genetic and sex-linked factors influence nonimmune clearance of HBs antigen in mice. If similar factors exist in man they may explain some of the variation in clinical manifestation of HBV infection.     

An enzyme-linked immunosorbent assay for quantitation of Haemophilus Influenzae type b polysaccharide-specific IgG1 and IgG2 in human and infant rhesus monkey sera.

An enzyme-linked immunosorbent assay (ELISA) has been developed and validated to quantitate IgG1 and IgG2 antibody to polyribosyl-ribitol phosphate (PRP), the capsular polysaccharide of Haemophilus influenzae type b (Hib). The sera of children and infant Rhesus monkeys immunized with an Hib conjugate vaccine composed of Hib PRP covalently linked to an outer membrane protein complex (OMPC) from Neisseria meningitidis serogroup B (PedvaxHIB, PRP-OMPC, Merck, Sharp and Dohme Research Laboratories). The solid-phase antigen employed in the ELISA is a conjugate of PRP to human serum albumin. The enzyme-labeled antibody is alkaline phosphatase-conjugated mouse monoclonal (mAb) anti-human IgG1 or IgG2. A human serum standard was calibrated using parallel titrations with a known antibody standard. The geometric mean titer (GMT) of the anti-PRP IgG1 response to one dose of PedvaxHIB was 3.87 micrograms/ml (n = 82), 11.80 micrograms/ml (n = 62) and 14.57 micrograms/ml (n = 74) in infants and children 12 to 17 months, 18 to 23 months and greater than or equal to 24 months old, respectively. Infants 2 to 11 months old responded with an IgG1 anti-PRP response of 7.10 micrograms/ml while infant monkeys responded with a GMT of 150.65 (n = 9) after two doses of vaccine. The anti-PRP IgG2 GMT responses in all groups were less than 0.25 micrograms/ml, except for humans greater than or equal to 18-months old who exhibited a GMT of greater than or equal to 0.40 micrograms/ml (n = 75). PedvaxHIB, immunization of human infants and children and infant Rhesus monkeys elicits primarily an IgG1 response to PRP. The monkey model appears to be a reliable indicator of the human immune response.