The Complement Content of Human Sera With Especial Reference to Malaria 1

Abstract

Our interest in the complement content of sera from healthy and diseased individuals was initiated by chance observations on the cephalincholesterol flocculation test (1). 'In our first performance of the test we inadvertently included several sera which had been inactivated and stored in the refrigerator over-night. All of these gave positive readings at 24 hours. Repetition of these tests, using sera from the same individuals, but fresh samples which were less than four hours old, yielded some negative and some positive reactions.It appeared that heating sera at 560 C. for 30 minutes might have played a part in the nonspecific reactions with the cephalin-cholesterol antigen. Sera from 20 healthy individuals were therefore tested before and after inactivation.None of the 20 sera gave positive readings before inactivation, whereas five gave readings after heating which would be considered significant.These results demonstrated that certain normal sera may be altered by inactivation to the extent that they give false positive cephalin-cholesterol reactions. The mechanism of inactivation is not altogether understood. One important result has to do with the destruction of the hemolytic property of the serum. Denaturation of proteins may occur and there may be loss of stabilizing property. However, determination of the complement content of these 20 sera, according to methods described later in this report, revealed no differences which could be related to the cephalin-cholesterol flocculation test. Later it was found that the addition of varying amounts of complement or albumin to positively reacting sera, or to normal sera which gave positive reactions after inactivation, did not inhibit the positive reaction.

Invasive African nontyphoidal Salmonella requires high levels of complement for cell-free antibody-dependent killing

“…This clinical association is well recognized in Africa (Graham et al, 2000;Bronzan et al, 2007). Hypocomplementemia, a marked decrease of serum complement components, is often observed in children and adults with acute malaria (Dulaney, 1947;Siddique and Ahmed, 1995). Hypocomplementemia in African patients with malaria may therefore increase susceptibility to S. Typhimurium, giving rise to co-infection with malaria and Salmonella.…”

Relationship of Serum Complement Levels to Events of the Malarial Paroxysm

“…As long ago as 1922, Radosavljevic concluded from semiquantitative tests then available that serum C' activity was reduced during the paroxysm in human malaria (4). In 1948 with the use of quantitative assays for C', Dulaney reported a general association of reduced C' in patients with malaria (5). More recent studies in heavily infected monkeys have found a striking depletion of C' shortly before death (6), and variation in C' and C' components levels during schizogony (7).…”

Serum Complement Levels in Systemic Lupus Erythematosus and Other Diseases

“…The high serum complement levels observed in obstructive jaundice were also found by Dulaney (1948), by Jordan (1953) and by Mandel and Lange (1955). Fischel (1953) and Boltax and Fischel (1956) described raised serum complement levels in tissue destruction.…”