REGULATION OF THE IMMUNE-RESPONSE IN PLASMODIUM-FALCIPARUM MALARIA .2. ANTIGEN SPECIFIC PROLIFERATIVE RESPONSES INVITRO

  • 1 January 1983
    • journal article
    • research article
    • Vol. 53  (2) , 345-353
Abstract
The antigen-induced DNA synthesis in vitro in lymphocytes from patients with acute P. falciparum malaria was investigated. The patients and healthy controls from Sweden or Colombia were the same as those studied in the accompanying paper (Troye-Blomberg et al.). The malarial antigens used were sonicated membrane preparations or purified and concentrated supernatants from in vitro cultures of P. falciparum; similar preparations derived from normal human erythrocytes served as control antigen. In the patients'' lymphocytes P. falciparum antigens induced a weak or moderate but significant stimulation of DNA synthesis, peaking after 3-4 days of incubation. This early response was specific for P. falciparum since it was not obtained with lymphocytes from healthy donors nor with those from patients with acute P. vivax or P. ovale malaria. No antigen-induced response was seen in about half of the P. falciparum patients. In a few negative cases, available for consecutive testing, positive reactions were seen with lymphocytes taken 2 wk after infection when the blood of these patients was free of parasites. The early response induced in patients'' lymphocytes to the P. falciparum antigens was not obtained with RBC [red blood cell] antigen. These preparations frequently induced a response rising to significant levels later during incubation (day 5-6). Similar delayed responses were obtained when either patients'' or control donors'' lymphocytes were exposed to the P. falciparum antigens. Apparently, both the RBC and the parasite preparations contained mitogenic substances affecting human lymphocytes in general and easily obscuring the P. falciparum specific response seen only in the patients. This latter response was relatively low and short lived, suggesting that it reflected a secondary in vitro stimulation of in vitro primed lymphocytes and that it was regulated by suppressor mechanisms.