Search PubMed⌕ Search

Biomedical subjects

D B Amos

Publications and source records attributed to D B Amos.

At least 109 records · Page 6Linked to original sources
PubMed1975

The antiglobulin microcytotoxicity assay in HL-A genotyped families.

HL-A genotyping was accomplished in 30 families (8 black, 21 white, and 1 American Indian) based on serological results obtained by our ususal lymphocytotoxicity assays. Each family was further tested by an antiglobulin microcytotoxicity method. Segregation patterns obtained by the latter method, compared with those of the former, showed few discrepancies. HL-A-identical siblings were serologically similar by the antiglobulin assay with frequency of discordant reactions at the same level as that of our regular two-stage lymphocytotoxicity assay. The antiglobulin method was shown to be highly reproducible with 1.3% discordance between duplicate tests. Many sera employed in routine cytotoxicity testing gave positive reactions with all family members in the antiglobulin assay (39% all positive by antiglobulin versus 16% by the regular cytotoxicity test), so that this method has limited usefulness for routine HL-A typing. The antiglobulin assay may have particular value, however, for identifying HL-A haplotypes in families, especially non-Caucasian, which give infrequent positive reactions in the usual lymphocytotoxicity assays.

Antibodies, Anti-Idiotypic↗
PubMed1975

HL-A antigens in a Chinese population.

The HL-A antigens of a Chinese population now living on the island of Taiwan have been investigated with reagents obtained from and characterized in Caucasian populations and with antisera obtained from Chinese multiparous women. Both HL-A2, the most frequent specificity found, and HL-A9 appear highly heterogeneous in this Chinese population since groups of antisera used to define HL-A2 or 9 in Caucasians gave discordant reactions. Moreover, new associations were found using chi-square and cluster analyses, further demonstrating the complexity of HL-A in this Taiwanese population. Fourteen % of 1183 Chinese multipara sera and 237 sera from multiple tranfused individuals were lymphocytotoxic and could be placed by cluster analysis into three major groups.

Cytotoxicity Tests, Immunologic↗
PubMed1975

An analysis of the 4c complex of HL-A based on Indian populations.

Sera detecting part or all of the 4c group of HL-A antigenic specificities were compared in two American Indian populations, the Ixils and the Pimas, and in one Spanish-Indian hybrid population, the Mestizos of Peru. Several new variants appeared. These were not identical to HL-A5, W5 or W18. Two of the variants appeared to represent specificities Z57 and Z51 as described during the 1972 Histocompatibility Testing Workshop. In addition, three new specificities could be detected. These were Z42, Ao88 and Ao93. Z42, Ao88 appeared to belong to the 4c complex and Ao93, a new specificity of the second locus, may belong to this same cross-reactive group.

Antigen-Antibody Reactions↗
PubMed1975

HL-A, fertility and natural selection.

The antibodies occasionally produced in gravid females usually cause no adverse effects and the mother may become hyporesponsive. Exceptions may occur in some cases of abortion where frequency of antibodies appears to be unduly high. Sperm antigens in the mouse include T locus alleles as well as H-2 and H-Y. The T locus is involved in differentiation. T locus alleles are expressed on early but not late embryos. A search for similar factors in man is in progress. The antigenic differences between sperm and mother and between foetus and mother may be important in natural selection. It is possible that the union of sperm with ovum is non-random and that the ovum can select "compatible" sperm through recognition of cell surface markers present on sperm. Immunologic differences between mother and foetus may cause local "graft-versus-host" reactions in the placenta. This leads to increased placental size and may be a factor in hybrid vigour as well as a protective device.

Antibody Formation↗
PubMed1975

Analysis of an HL-A antiserum by iso-electric focusing.

An anti-HL-A 3 antiserum with cross-reacting activity for HL-A 1 and HL-A 11 was subjected to isoelectric focusing over a pH 5-8 gradient. The cytotoxic activity of the serum focused into three distinct peaks, one at the basic end of the gradient, one between pH 6 and pH 7 and one at the acidic end. The first and second peaks reacted with HL-A 3 positive cells and HL-A 3 negative cells positive for cross-reacting antigens. The third peak reacted only with HL-A 3 positive cells.

Antibody Specificity↗
PubMed1974

Genetic mapping of Ir locus in man: linkage to second locus of HL-A.

Fifty-seven members of a family that spanned three generations were studied for antigen E and ragweed skin sensitivity and HL-A antigens. There was significant association between the haplotype HL-A 2-12 and antigen E skin hypersensitivity (F = .22 to .26) in this family. The map order is first locus of HL-A, second locus of HL-A, and IrE. These determinants are considered to be part of the linkage group HL-1.

Adolescent↗