Type-Specific and Cross-Reactive Antibodies in Gram-Negative Bacteremia

Functional role of antibody against "core" glycolipid of Enterobacteriaceae.

“…The initial serologic studies of McCabe et al in human gram-negative septicemia indicated that anti-0-antibody titers were not protective against shock and death in contrast to antibody against CGL (9). One problem in human studies is that it is not always possible to precisely date the onset of infection and it is uncertain how "initial" antibody titers are acquired, though presumably this is due to antecedent or chronic infection.…”

“…Secondly, we wanted to evaluate the activity of this antibody as an opsonin, bactericidin, and antitoxin. Third, we wished to assess the relative protective role of typespecific vs. cross-reactive antibody in animal model systems, inasmuch as one study has suggested that cross-reactive antibody appears more protective than type-specific antibody (9). Fourth, we felt there was need to assess the role of antibody using a variety of heterologous challenges including serum-resistant and serum-sensitive strains, since there is little information on host protection after challenge with both types of organisms.…”

DIFFERENTIAL AGGLUTINATION OF PARTICULATE Vi AND O ANTIGENS BY THE IgM AND IgG CLASS ANTIBODIES

“…The apparent lack of correlation between levels of serum agglutinin and protection against infection with typhoid bacilli observed by the same group of authors (Hornick et al, 1970) cannot be regarded as conclusive evidence that such antibodies are of no protective value. McGabe, Kreger and Johns (1972) reported that in gram-negative bacteraemia the levels of O agglutinins to enterobacteria did not correlate with protection against infection with the corresponding bacterial strains, but in a later study (Zinner and McGabe, 1976) they found that protection correlated with residual O agglutinin levels after treatment of the sera with mercaptoethanol, i.e., correlated with the IgG class O agglutinin levels. Their studies and ours thus indicate the unreliability of serum agglutinin level as a measurement of total antibody concentration, and emphasize the importance of studying the differential secondary biological properties of antibodies in relation to both their antigen specificities and their individual immunoglobulin classes.…”

Modulation of human platelet protein kinase C by endotoxic lipid A.

“…In experiments using a murine macro-(3). Moreover, higher titers of antibodies, directed against the I-line RAW264.7, a similar range of concentrations lipid A-containing core of gram-negative bacteria, protected I and its monosaccharide precursor lipid X, to those patients from irreversible changes of endotoxic shock in gramir study were inducing activation of protein kinase C negative bacteremia (47). Modulation of protein kinase C in :)ysis of phosphatidylinositol with a concomitant in-human platelets by endotoxic lipid A indicates that this pivotal synthesis of prostaglandins (24,44 (13,43).'…”

“…Lechanism through which endotoxic lipid A moduAlthough we do not have evidence that protein kinase C in -in kinase C in human platelets can involve a direct human platelets is directly accessible to endotoxic lipid A, the n with the enzyme in a manner similar to the acidic following points indicate that this is possible. (a) As demonpid, phosphatidyl serine, or an indirect interaction strated in other cells, the enzyme is translocated to the memctivation ofphospholipase C and subsequent genera-brane (13,43 47 is -25-50 times higher than PMA. The more tration is in the spleen, brain, and ganglia (9, 11).…”