INFLUENCE OF AZATHIOPRINE ON HUMORAL DEFENCE FACTORS AGAINSTESCHERICHIA COLIIN GERMFREE AND MONOCONTAMINATED RATS

Abstract

By means of radioisotope technique the influence of azathioprine on humoral defence factors against E. coli was studied on germfree and ex-germfree rats monocontaminated with E. roli. Using inactivated sera, by the addition of serum from germfree rats as a source of complement, titration of antibodies showed that the bactericidal activity of serum from azathioprine-treated rats was reduced in relation to control serum. By distinguishing the immunoglobulins on the basis of their sensitivity to 2-rnercaptoethanol, it was found that azathioprine blocked the production of 2-mercaptoethanol-resistant antibodies. The complement activity in the azathioprine-treated animals was not found to be decreased. Apart from complement other non-specific humoral factors against E. coli did not seem to par-Received 15.vi.73

INFLUENCE OF METHYLPREDNISOLONE ON COMPLEMENT ACTIVITY IN GERMFREE RATS AND ON ANTIBODY ACTIVITY TO ESCHERICHIA COLI IN MONOCONTAMINATED RATS

“…Inactivation of serum was obtained by heating at 56" C for 30 minutes ( 7 ) prior to antibody titration.…”

“…Determination of Complement Activity of sera from GF rats and GF rats treated with methylprednisolone (GFU) was performed after addition of 10 per cent inactivated conventional rat serum as a standard amount of antibody ( 7 ) .…”

“…of inactivated sera was performed after addition of 5 per cent GF serum as a standard amount of complement (7).…”

“…was based on mercapto-ethanol (ME) treatment of serum and subsequent alkylation by iodacetamide as previously described ( 7 ) .…”

“…was carried out as previously described, using 15 min as a standard period of incubation at 37" C (7,18). The opsonic activity of serum was studied by measuring its ability to induce uptake of 32Plabelled E. coli into polymorphonuclear neutrophils (PMN) which were suspended in medium containing 5 per cent of the serum to be tested.…”