Taq-I polymorphism in 3′ UTR of the IL-12B and association with IL-12p40 production from human PBMC

A wide array of studies has demonstrated differences in genotype and allele frequencies of cytokine gene polymorphisms depending on ethnicity and race. In this study, the frequency of Taq-I polymorphism in 3' untranslated region of IL-12B was investigated in two Bulgarian ethnic groups - Bulgarians and Turkish minority. No significant differences of genotype and allele frequencies were observed between these groups. Genotype distribution in the total group of Bulgarian citizens was: AA (61%), CA (32%) and CC (7%), and the allele frequency of 16974 A allele was 0.77. We also evaluated whether this polymorphism affects IL-12p40 production from human PBMC after stimulation. We demonstrated that association between genotype and IL-12p40 production by stimulated PBMC depends on the stimuli used. Our results indicated a significantly decreased IL-12 p40 secretion for the following order of genotypes: AA>CA>CC, after stimulation of PBMC with C3-binding glycoprotein (C3bgp) in contrast to lipopolysaccharide, phytohaemagglutinin and pokeweed mitogen.