A comparison of the lymphoproliferative capacity of pokeweed mitogen (PWM) and phytohaemagglutinin (PHA) in CCR-5 wild-type and heterozygous HIV-infected and uninfected subjects

Abstract

Effect of CCR-5 delta 32 heterozygosity in immunological protection was studied by a lymphocyte proliferation assay. Twenty of 86 HIV+ and eight of 32 healthy subjects showed heterozygous mutation (wt/mut) of the CCR-5 gene. Lymphocyte proliferation to pokeweed mitogen was found significantly higher ( P < 0.005) in wt/mut versus wild type homozygous (wt/wt) HIV+ subjects in groups with CD4 > 500 and CD4 < 200 cell/ µL. Phytohaemagglutinin induced stronger proliferation of cells from wt/mut HIV+ subjects with CD4 < 200 cell/ µL ( P = 0.03). Decline of lymphocyte response was more significant among wt/wt groups with different CD4+ cell counts than that between wt/mut groups to both mitogens. Reduced number of CCR-5 receptors on CD4+ cells may decrease the ability of HIV-1 envelope glycoproteins to transduce intracellular signals through CCR-5. Mutation in CCR-5 gene seems to have a benefit in preventing T-cells from HIV envelope-mediated immunopathogenic effects and maintain a relatively normal response to lectins.