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Biomedical subjects

D B Amos

Publications and source records attributed to D B Amos.

At least 37 records · Page 2Linked to original sources
PubMed1983

Analysis of the B10.D2-H-2dml mutant with monoclonal antibodies.

We compared H-2D products of B10.D2 and the mutant B10.D2-H-2dml spleen cells using two monoclonal antibodies designated D3.179 and S11.7. D3.179 reacts with public specificities and appears to define more than one product as shown by cytotoxicity and binding studies. Strong reactivity was obtained in both binding and cytotoxicity to B10.D2 and marginal cytotoxicity and low binding were observed with B10.D2-H-2dml cells. The second monoclonal antibody S11.7, in contrast, reacts only with H-2Dd bearing strains and gave strong binding to B10.D2-H-2dml and weaker binding to B10.D2. Taken together, the observations indicate that the mutant not only expresses H-2D encoded antigens but bears quantitatively greater amounts of some specificities than the parent. A product of approximately 46,000 daltons was immunoprecipitated from B10.D2 cells by D3.179. Very small amounts of this product were seen in B10.D2-H-2dml immunoprecipitates.

Animals↗
PubMed1983

SFR3-DR5, a monoclonal antibody with HLA-DR5 specificity.

We have developed a monoclonal antibody with HLA-DR5 serologic specificity. The antibody, SFR3-DR5, binds specifically to DR5-positive lymphoblastoid cell lines, and immunoprecipitates alpha- and beta-chains characteristic of DR antigens from them. Cytotoxic activity of the antibody segregates with the DR5-bearing haplotype in a family. The antibody reacted with the cells of 16 of 17 DR5 individuals and was negative on all DR5-negative cells tested. SFR3-DR5 reacted weakly with PWM-activated cells of the single DR5 individual whose B lymphocytes were unreactive with the monoclonal antibody by cytotoxicity. Possible interpretations of these results are discussed.

Animals↗
PubMed1983

Shared HLA antigens and reproductive performance among Hutterites.

Shared histocompatibility antigens between spouses may affect reproductive outcome adversely as a result of prenatal selection against compatible fetuses. Evidence from both animal and human studies suggest that histocompatible fetuses may not initiate a maternal immunologic response that prevents rejection of the embryo. Therefore, parents sharing HLA antigens may produce compatible fetuses and consequently experience a greater frequency of early fetal losses and show poorer reproductive outcome than couples not sharing antigens. In the Hutterites, an inbred human isolate that proscribes contraception, we tested the hypothesis that couples sharing HLA antigens have poorer reproductive outcomes than couples who do not. The Hutterites are characterized by high fertility and large family sizes. Couples that share zero (no. = 21), one (no. = 15), and more than one (no. = 10) HLA-A or HLA-B antigens were compared for reproductive performance. Median intervals between births were larger among couples that share more than one antigen in eight of 11 intervals examined. In addition, the median intervals from marriage to first, fifth, and tenth birth were consistently larger among couples that share more than one antigen. Differences among the groups appear to become larger with increasing parity, suggesting that the effect of histocompatibility on reproductive performance becomes more evident in later pregnancies. These differences in reproductive performance between couples that share zero, one, or more than one HLA-A or HLA-B antigens may have significant evolutionary consequences. However, our results demonstrate that sharing HLA antigens does not preclude normal pregnancy and caution should be exercised before concluding that shared HLA antigens are solely responsible for repeated fetal losses.

Birth Intervals↗
PubMed1982

Ra3 skin test response and HLA-A2, antigen E, and IgE: evidence of interactions between antigen E and HLA.

A positive association of Ra3 skin test responses with HLA-A2 has previously been reported to be evident in individuals with low IgE levels and to a greater extent in these individuals than those with high IgE levels. We give evidence based on an analysis of data from 133 individuals that Ra3 response is positively correlated with HLA-A2 among individuals with low Antigen E response and negatively associated with HLA-A2 among individuals with high Antigen E response. Furthermore, we have evidence that any observed interaction between Ra3, IgE, and HLA-A2 can be explained by the correlation between IgE and Antigen E response, and that it is Antigen E response which interacts in the relationship between HLA-A2 and Ra3 skin test response.

Alleles↗
PubMed1982

A monoclonal antibody directed against the HLA-Bw6 epitope.

A cytotoxic monoclonal antibody, SFR8-B6, produced by immunizing KGH rats with partially purified glycoprotein from JY, a human B lymphoblastoid cell line, detects HLA-Bw6, a unique public antigen on the HLA-B molecule. By cytotoxicity, SFR8-B6 has complete concordance with the presence of Bw6 as defined by alloantisera, and its reactivity segregates with HLA in families. Because sera detecting Bw4 and Bw6 are rare, this monoclonal antibody has value as a perpetual standard. In addition, SFR8-B6 offers potential as a probe for investigating the molecular relationships of HLA antigens.

Animals↗
PubMed1981

Natural killing and antibody-dependent cellular cytotoxicity in specific-pathogen-free miniature swine and germ-free piglets. II. Ontogenic development development of NK and ADCC.

The ontogenic development of natural killing (NK) and antibody-dependent cellular cytotoxicity (ADCC) in germ-free and specific-pathogen-fee (SPF) miniature swine were compared. Activities of NK and ADCC were tested by a short-term (2.5 to 4 h) 51Cr-labelled human myeloid cell line K562 and TNP-conjugated human B-cell line SB as target cells for NK and ADCC, respectively. Animals obtained by aseptic hysterectomy 3-5 days prior to term showed ADCC activities similar to adult levels but lacked NK activity. Hysterectomy-derived piglets which were colostrum-deprived and maintained in germ-free isolators developed NK activity at 3-4 weeks of age. In comparison, naturally-farrowed, colostrum-fed piglets maintained in our SPF facility developed NK activity at 2-3 weeks of age. Thereafter, there was no significant difference in the levels of either NK or ADCC between germ-free and SPF animals. This suggests that microbial flora and environment do not affect the development of effector cells for ADCC but do play some role in the maturation of NK cells during ontogeny. The difference in ontogeny of NK an ADCC further support our previous suggestion that the effector cells for NK and ADCC in swine are distinct sub-populations.

Animals↗
PubMed1981

Paired H-2-specific monoclonal antibodies react differently to red cells and lymphocytes.

Two hybrid clones from a fusion of C57BL/6 anti-DBA/2 spleen cells and the myeloma line Sp2/0 secrete antibodies reactive with a product of the murine major histocompatibility complex (MHC). The two antibodies are provisionally designated S13.11 and S13.29. Both react in rabbit-complement-mediated cytotoxicity with spleen cells of H-2d, H-2f, H-2r, and H-2p strains. In addition, both antibodies hemagglutinate red blood cells from these strains. S13.11 is also cytotoxic for H-2a, H-2k, H-2u, and H-2v spleen cells but does not hemagglutinate red blood cells from mice bearing these haplotypes. With the exception of H-2v, this strain pattern mimics the public specificity H-28. Quantitative absorption of S13.11 shows that H-2d cells are twice as efficient as H-2k cells in their ability to remove the S13.11 antibody. S13.29 reacts weakly in cytotoxicity with H-2k spleen cells and does not react with cells from H-2u or H-2v. Blocking studies indicate that S13.11 and S13.29 react with the same or a closely related molecule on the cell surface.

Animals↗
PubMed1981

HLA antigens and immunoglobulin allotypes in patients with malignant melanoma.

HLA antigens and Gm, A2m, and Km allotypes were examined in Caucasian patients with malignant melanoma. No significant associations were found for any of the HLA antigens tested. Significant association was found with Gm(2), and the relative risk for individuals with this marker was calculated at 1.9. The data indicate that Caucasians positive for Gm(2) are almost twice as likely to develop malignant melanoma as those without this marker.

HLA Antigens↗
PubMed1981

Statistical methods for studying homozygous typing cells of unknown specificity.

A situation can arise in D typing in which the HLA (A,B,C,D, or DR) specificities of the responders are known and the specificities of the HTC's are unknown. The most powerful and direct method of detecting association between the unknown stimulator (HTC) and any given HLA specificity is by comparing the observed double normalized values (DNV's) of individuals known to be positive for the specificity with the DNV's of negative individuals. This can be done by comparing the two groups with a Kolmogorov-Smirnov test (K-S test), an established statistical procedure for evaluating correlation between continuous variables, such as the DNV, and discrete variables (such as presence of D type). The application of the K-S test will generate as a "cutoff" value of point that maximizes the average of the frequencies of correct assignments in D positives and D negatives. We also propose an alternative method of computing the "r" value. We have analyzed 49 HTC's from the 8th International Workshop and present the association observed with the D and DR specificities.

Alleles↗
PubMed1981

Mysteries of the Amerindians.

Several South, Central and North American Indian populations have been characterized over the past 9 years. A summary is given here. Very few major antigens have been found, namely A2, A9, A28 and Aw31 and B5, B15, Bw16, Bw35 and B40. However, several known splits of these antigens have been identified, and new variants are also likely. Immunogenetic analyses of the Amerindians should be able to provide clues both to the origins of the Amerindian cultures and migrations of early man, and also provide new insights into the antigens and the loci of the MHC.

Blood Grouping and Crossmatching↗
PubMed1981

The effects of electrophoretically "slow" and "fast" alpha-2 macroglobulin on mixed lymphocyte cultures.

It has been determined that alpha-2 macroglobulin (alpha 2M) is more suppressive of a mixed lymphocyte response (MLR) when complexed with proteinase than in its "native" state. Other alpha 2M preparations showed a moderate level of MLR suppression, but it is unlikely that this is a result of interaction with cellular proteinases. A panel of other proteinase inhibitors (alpha 1 PI, SBTI, BPTI, TLCK) did not suppress the MLR to the same extent as alpha 2M either when bound with or free from trypsin. A dose-responsive pattern of MLR suppression similar to that observed with purified proteinase-complexed alpha 2M was seen with serum containing proteinase-complexed alpha 2M. The population of cells that apparently conveys the suppressive property is the adherent cells (putative monocytes), which can reduce the MLR almost as well as unfractionated cells when exposed to alpha 2M. Most of these properties of alpha 2M were demonstrable in "serumless" medium with qualitative similarity to the MLR obtained in cultures performed with conventional serum supplemented medium. It was found that alpha 2M-trypsin complexes must be presented at or near culture initiation and remain in contact with the cells for a minimum of approximately 4 hr to have its optimum effect.

Blood↗
PubMed1981

Familial predisposition to filarial infection--not linked to HLA-A or-B locus specificities.

Two hundred and twenty-five Polynesians were selected from a larger study population for the evaluation of potential genetic influences on the susceptibility to bancroftian filariasis. Analysis showed that there was significantly familial clustering of patients with filariasis and that this clustering was most compatible with genetic transmission of disease susceptibility. The data best fit a model in which the hypothetical gene for filariasis was recessive with a frequency of 0.82 +/- 0.15 in the population and a penetrance of 0.62 +/- 0.14. The alternative hypothesis that susceptibility was environmentally (i.e., not genetically) determined was also compatible with the data but was estimated to be 1.9 times less likely to account for the observed findings than the genetic hypothesis. Extensive evaluation of HLA-A and -B locus specificities failed to detect significant linkage either between particular antigen specificities and the clinical manifestations of filariasis or between individual haplotypes (indicated by HLA markers in studies of large families) and the predisposition to filarial infection or disease.

Adolescent↗
PubMed1981

Natural killing (NK) and antibody-dependent cellular cytotoxicity (ADCC) in specific pathogen-free (SPF) miniature swine and germfree piglets. III. Two distinct effector cells for NK and ADCC.

Effect of "anti-NK" sera on NK and ADCC activities was examined to study further the relationship between the effector cells for NK and ADCC in specific pathogen-free miniature swine. An appropriate dilution of "anti-NK" sera that had no effect on ADCC activity not only inhibited NK activity but also eliminated NK cells in the presence of C which supports the presence of NK cells distinct from K cells for ADCC.

Animals↗
PubMed1980

Genetic mapping of the hemochromatosis locus on chromosome six.

The purpose of this paper is to report a pedigree with hereditary hemochromatosis in which a recombination between the HLA-A and B loci occurred. Both the maternal and paternal HLA-A3, B7 haplotypes were carrying an allele for hemochromatosis. The A3, B12 haplotype of the proband was a recombinant of the maternal A3, B7 and A28, B12 haplotypes. The hemochromatosis locus segregated with the HLA-A locus and not with the HLA-B locus. Thus, the hemochromatosis locus maps in close proximity to the HLA-A locus.

Adult↗