Corticosterone regulation of the effector function of malarial immunity during pregnancy

Abstract

In the experimental Plasmodium berghei mouse model, as in human malaria, reduced maternal responsiveness and even loss of immunity were observed during pregnancy. Loss of immunity in the second half of pregnancy occurred during a period of elevated plasma corticoid levels. Further analysis showed that plasma corticoid levels were significantly higher in immunodepressed mice than in mice that remained immune throughout pregnancy. Plasma corticosterone levels differed increasingly from those in mice with persistent immunity towards recrudescence. In nonimmune infected controls, however, only a slight increase in plasma corticosterone, already present during the subpatent period, was measured. Blocking of maternal corticoid production by adrenalectomy delayed the increase of plasma corticosterone (fetoplacental origin) and reduced the number of mice that lost immunity during pregnancy considerably. The role of various plasma corticoid levels in the regulation of effector function of immunity during pregnancy is discussed.

ACTH‐dependent modulation of malaria immunity in mice

“…Loss of immunity during pregnancy was related to increased levels of both total and free plasma corticosterone. Moreover, when the increase in plasma corticosterone in the mother was prevented by adrenalectomy before pregnancy, loss of immunity during pregnancy was drastically reduced (van Zon et al 1982). These results suggested that reduced immune reactivity during pregnancy causing loss of a pre-existing anti-malaria immunity was causally related to pregnancy-dependent changes in corticosterone levels.…”

“…Corticosterone in the minipump (25 pg/pl) resulted in a calculated release of 258 pg/24 h. Although this dose seems high in relation to the basal plasma level of 0.1 pg/ml plasma (van Zon et al 1982), it did not result in a detectable increase in the plasma corticosterone concentration during the 3 week period following implantation of the minipumps (results not shown).…”

“…Total plasma corticosterone was measured by a radioimmunoassay (RIA) using a sheep anti-corticosterone serum (gift from T. Benraad, Department of Experimental and Chemical Endocrinology, University of Nijmegen) as described previously (van Zon et al 1982). The concentration of free corticosterone in the plasma was determined by equilibrium dialysis according to the method of Ross (1980), modified as described in detail elsewhere (van Zon et al 1983).…”

“…van Zon, Department of Cytology and Histology, University of Nijmegen, Geert Grooteplein N21, 6500 HB Nijmegan, The Netherlands. (van Zon et al 1982(van Zon et al , 1983 and could be prevented by adrenalectomy performed before pregnancy. The observations suggested a causal relation between serum corticosterone levels during pregnancy and loss of malaria immunity.…”

Impairment of T Cell‐Mediated Immunity to Listeria monocytogenes in Pregnant Mice

“…As a matter of fact, several authors have referred to increased susceptibility to infection or the exacerbation of infectious diseases caused by bacteria (3,22), viruses (17,22,38), or protozoa (22,40) during pregnancy. In some experimental infections of mice, pregnancy is reported to result in impaired protection against some kinds of M. SANO ET AL viruses (4,10,13,14), Plasmodium berghei (43,44), and Listeria monocytogenes (19,25). L. monocytogenes is one of the bacteria which induce typical T cell-mediated immunity.…”