Highlights of complement research during the past twenty-five years

The genetic influence on serum haemolytic complement levels in cattle

Total serum haemolytic complement (HC) activity has been determined in 130 young bulls of the Norwegian Red Cattle Breed (NRF). A highly significant sire effect (p less than 0.01) on HC with a corresponding heritability of about 0.75 was estimated. Evidence of any simple mode of inheritance is not produced but the distribution patterns of HC indicate influences of relatively few genes.

Development of the concept of immunologic specificity: IV

We have attempted, in this series of essays on the development of the concept of immunologic specificity, to trace the history of one of the most central ideas in immunology (and indeed in biology in general). The result must be viewed as preliminary and incomplete and as an invitation to others to add, to amend, and even to disprove. Nevertheless, several interesting conclusions may be drawn, which reveal much about the workings of immunology in particular, and perhaps science in general. First, the roots of any important scientific concept (such as that of immunologic specificity) do not grow in isolation; they draw nourishment from many other disciplines. Similarly, the growth of an important concept within a given discipline will have far-reaching implications and fruits for other fields of science. Second, we may note a marked change in the manner in which immunology is currently practiced, compared with that of the end of the last century. The quantum leaps forward in funding, in numbers of scientists, and in masses of crucial data have not been without a certain cost--the substantial reduction in elegant personal style that characterized so many of our scientific forebears, and that makes so pleasant the reading of their reports. Finally, we see again and again how much his philosophical bases and disciplinary upbringing determine a scientist's approach, the questions that he asks, and the type of answers he will accept. Throughout much of immunology's history, as Jerne put it so well (44), cis- and trans-immunologists hardly spoke to one another. Or rather, a cis-immunologist sometimes spoke to a trans-immunologist, but the latter rarely answered! Fortunately, one of the attributes of scientific progress is a merging of these disparate languages, and eventual mutual comprehension.

Immunological properties of glycolipids from membranes of Acholeplasma laidlawii

Glycolipids, the predominant class of lipids in the membranes of Acholeplasma laidlawii, are the haptenic determinants that react with anti-A. Laidlawii serum to fix complement. The predominant complement-fixing activity of the membrane glycolipids was associated with the monoglucoysyl diglyceride, diglucosyl diglyceride, glycerlphosphoryl diglucosyl diglyceride (GPDD), and an unknown lipid B, which did not react with ninhydrin but release glucose and glycerol and traces of phosphorus upon hydrolysis. The glycolipids monoglucosyl diglyceride and diglucosyl diglyceride or GPDD and unknown lipid B were paired as a result of their cross-reactions with selective antisera prepared with the aid of reconstituted membrane complexes containing membrane lipids. Reconstituted membrane complexes assembled from [14C]monoglucosyl diglyceride and delipidated membrane proteins gave optimal complement fixation titers before saturation of the complexes with the ]14C]monoglucosyl diglyceride. The phosphoglycolipid of the membrane, GPDD, was anticomplementary as a pure lipid, a cholesterol liposome, and a reconstituted membrane complex. This anticomplementary activity, which was caused by 3 mug of pure GPDD, affected both human and guinea pig complement. Although human C1, C4, C3, and C5 were not inhibited by GPDD, C2 was inhibited 10-fold by reconstituted membrane complexes containing 150 mug of GPDD. A role for this phosphoglycolipid is discussed in the hypothetical mechanism of inhibition of C2 attachment to SAC1, 4 sites.

Immunochemical analyses of membrane-bound complement. Detection of the terminal complement complex and its similarity to "intrinsic" erythrocyte membrane proteins

(1) Membranes of sheep erythrocytes lysed with antibody and human or rabbit complement were solubilized in non-ionic detergents (Triton X-100 or Berol EMU-043) and analysed immunochemically using antisera directed against individual complement components. The precipitation behaviour of membrane-bound C3, C5, C6 and C9 components of complement was examined by immuno-double diffusion, rocket- and crossed immunoelectrophoresis performed in agarose gels containing 1% non-ionic detergent. (2) Membrane-bound C5, C6 and C9 are antigenically altered compared with the native (serum) components. (3) Immuno-double diffusion in the presence of non-ionic detergents reveals formation of C5-C6-C9 complexes on the membranes; these complexes are stable in non-ionic detergent. No complex formation was detected in serum between native C5, C6 and C9 components. There was also no evidence for complexing between membrane-bound C3, C4 or membrane proteins and the "late-reacting" complement components. (4) The extractability of complement components by various manipulations has been studied by use of quantitative rocket immunoelectrophoresis. Up to 65% of membrane-bound C3 is readily extracted by dialysis of membranes against 1mM EDTA, pH 8.0, 100 mM EDTA, pH 8.0, 1.2 NaCl plus or minus EDTA, by extraction in isotonic buffers at 37 degrees C, by heating at 45 degrees C over several hours, or by treating membranes with 1 mM p-chloromercuribenzoate sulfonate. In contrast, less than 6% of the terminal complement complex can be eluted by any of the described methods or combination of methods. (5) Our data suggest that the terminal complement complex associates with membrane "core" components through apolar interactions.