Some In Vitro Invasion Inhibition of Red Cells by In Vivo Non‐protective Anti‐LDH Antibodies of Plasmodium berghei

In Plasmodium berghei, sephadex G‐200 purified lactate dehydrogenase (LDH) fraction immunized mice did not exhibit protection when challenged with 1 × 10⁶P. berghei‐parasitized erythrocytes. However, LDH immunized mice seroconverted and showed an antibody titre of 1:2048 by indirect haemagglutination (IHA) and 1:160 by indirect fluorescent antibody (IFA) assays. Fluorescence was distributed evenly on P. berghei‐parasitized red cells showing no specific location of parasite LDH. Anti‐LDH antibodies supplemented in 19 h in vitro culture of P. berghei exhibited 9.2% invasion inhibition into the fresh red cells.