Mixed Lymphocyte Culture Technique: Standardization of a Test-System with 105 Responding and 105 Stimulating Lymphocytes per 1 ml

An MLC test system is described utilizing 10⁵ responding and 10⁵ stimulating lymphocytes in a total of 1 ml of culture medium. Some of the variables of the test have been evaluated and the reproducibility of the test within a given day and between days investigated according to a Workshop protocol. This system was first applied to three groups: HL-A identical siblings, one haplotype different family members and two haplotype different individuals. Within each group, the log converted stimulation ratios are normally distributed, allowing the use of simple statistical analysis in repeated testings. In addition, a group of weakly positive MLC reactions can be detected. This group includes the LD identical but SD different sibling combinations. Within the same group we find some unrelated HL-A sero-identical combinations and the so-called LD typing response, used to identify LD determinants by means of LD and SD homozygous stimulating test cells.
It is concluded that this MLC test system allows identification of identical combinations, weakly positive combinations and one and two haplotype responses even within unrelated combinations. This test system may have advantages over the microtiter test system because the large culture volume gives a low concentration of blastogenic factors in typing responses.