| Abstract: | Blood samples were collected from healthy twin pairs of the same sex, living in the same households and attending the same schools. The occurrence of HLA antigens and seven red cell antigens was determined. The serum titres of antibodies against three different components of measles virus were measured by haemagglutination inhibition, by haemolysis inhibition and by nucleocapsid complement fixation tests. The variability of titres within twin pairs was significantly greater among seventy dizygotic twins than among seventy monozygotic twins, suggesting an influence of genetic factors on the measles antibody response. However, no evidence for a genetic linkage between HLA loci and the loci involved in the antibody response was apparent, since the variability of antibody titres among eighteen dizygotic pairs with common HLA haplotypes was about similar to that among twenty-three pairs with different haplotypes. A possible association between antibody titres and HLA-A3 and B7 antigens was also analysed in the present material. The comparisons were made between groups of single individuals in the twin pairs. The presence or absence of HLA-A3 antigen did not significantly influence the mean titres of groups. However, in two out of six comparisons, the mean antibody titre was significantly higher in the group of individuals who had HLA-B7. |
