Biomedical subjects

M E Van Der Tol

Publications and source records attributed to M E Van Der Tol.

3 recordsLinked to original sources

PubMed1979

Escherichia coli K antigen in relation to serum-induced lysis and phagocytosis.

The presence of capsular polysaccharides (K antigens) and their relation to phagocytosis and sensitivity to the lytic action of serum of 26 strains of E. coli isolated from stools of healthy volunteers and from blood cultures were studied. Four of 12 strains isolated from stool cultures and 12 (86%) of the 14 strains isolated from blood cultures possessed K antigen. Three of the 12 strains isolated from stool cultures and seven of the 14 isolated from blood cultures were resistant to uptake by polymorphonuclear leucocytes; these resistant strains contained large amounts of K antigen. By contrast 10 strains, three with low amounts of K antigen and seven without detectable amounts of K antigen, were readily phagocytosed. Thus it appears that K antigen renders E. coli resistant to phagocytosis. Only four (15%) of the 26 strains were sensitive to serum lysis and there was no correlation between the presence of K antigen and the resistance to serum lysis.

Antigens, Bacterial↗

PubMed1979

Staphylococcus aureus opsonization mediated via the classical and alternative complement pathways. A kinetic study using MgEGTA chelated serum and human sera deficient in IgG and complement factors C1s and C2.

Staphylococcus aureus opsonization was studied kinetically by: (1) determination of the uptake of [3H]-thymidine labelled bacteria by human PMN's; (2) fluorescent anti-C3 and anti-IgG staining of opsonized bacteria; and (3) measuring bacterial complement consumption. Maximum opsonization in normal serum occurred within 5 min of incubation. About 80% of staphylococci were then taken up by PMN's, and IgG and C3b could be detected on the bacterial surface. In the absence of a functional classical complement pathway, as in sera deficient in C1s and C2 and in MgEGTA chelated serum, maximal opsonization was only achieved after 30--60 min incubation. Opsonization in IgG deficient serum occurred at a rate similar to that found in C2 deficient or MgEGTA chelated serum. Opsonization was greatly enhanced when sera were reconstituted. It was concluded that in IgG deficient serum Staphylococcus aureus opsonization is mediated via the alternative complement pathway. Dilution of normal serum primarily affected the classical complement pathway, resulting in a decreased rate of opsonization. In normal serum IgG did not appear to be a rate-limiting factor. S. Aureus opsonization was best studied by the phagocytosis assay and the fluorescent-antibody technique. Measuring haemolytic complement consumption was found to be an insensitive indicator of bacterial complement activation and opsonization.

Complement Activation↗

PubMed1979

The role of Staphylococcus aureus cell-wall peptidoglycan, teichoic acid and protein A in the processes of complement activation and opsonization.

The role of cell-wall peptidoglycan, teichoic acid and protein A in the processes of Staphylococcus aureus complement activation and opsonization was investigated. CH50 consumption studies reveal that, although all cell-surface fractions were capable of activating the classical C pathway, only peptidoglycan consumed C via the alternative pathway. Using a quantitative immunofluorescence assay, peptidoglycan was shown to bind C3 molecules via the classical as well as via the alternative C pathway and in the absence of IgG and IgA class antibodies. C activation via the classical and the alternative pathway could be distinguished by kinetic analysis. By comparing the rates of staphylococcal C consumption, C3 fixation and opsonization it was found that the CH50 consumption assay is a relatively insensitive method and may yield results that do not necessarily reflect the process of bacterial opsonization.

Complement Activation↗