DISSOCIATIVE EFFECTS OF MALARIAL INFECTION ON HUMORAL AND CELL-MEDIATED-IMMUNITY IN MICE

  • 1 January 1979
    • journal article
    • research article
    • Vol. 37  (1) , 35-44
Abstract
The effect of malarial infection on immune responses was studied in mice. Sheep red blood cells (SRBC) were injected 2 days before or at the same time as infection with Plasmodium berghei. There was a marked increase in the number of splenic plaque forming cells (PFC) induced by SRBC as compared with uninfected controls. When SRBC were injected 2 days or more after the infection, the PFC response was significantly reduced. Cell-mediated immunity, exemplified by delayed-type hypersensitivity (DTH) to a number of antigens, was suppressed whether the infection was introduced before or after antigen stimulation. A similar effect was produced by injecting the host with the supernatant obtained following incubation in vitro of peripheral blood from heavily infected mice. When this supernatant was injected i.v. into normal mice at the same time as SRBC priming, it enhanced the humoral response to SRBC, but suppressed the DTH to SRBC. The coincident induction of this inverse relationship between humoral and cell-mediated immunities was clearly borne out by a dose response study using different dilutions of supernatant. The active component was of large MW (> 150,000), thermostable and not present in the serum of infected mice.