FIBRINOGEN PRECIPITATION BY STREPTOCOCCAL M PROTEIN : I. IDENTITY OF THE REACTANTS, AND STOICHIOMETRY OF THE REACTION

Evidence confirming the identity of fibrinogen-precipitating factor and streptococcal M protein is provided by the demonstration of bactericidal, mouse protective, and long chain-producing antibodies in the sera of rabbits immunized with washed M-fibrinogen precipitates. Two precipitin lines were observed in immunoelectrophoresis of human plasma vs. rabbit anti-M-fibrinogen antiserum; no precipitin reactions were observed between human serum and rabbit anti-M-fibrinogen antiserum. The reaction between M protein and fibrinogen was stoichiometric; a constant equimolar ratio of reactants was observed in precipitates formed with a wide range of M protein concentrations

FIBRINOGEN PRECIPITATION BY STREPTOCOCCAL M PROTEIN : II. RENAL LESIONS INDUCED BY INTRAVENOUS INJECTION OF M PROTEIN INTO MICE AND RATS

Intravenous injection of Type 1 streptococcal M protein into mice and rats produced lesions confined to renal glomeruli. Thrombi of eosinophilic amorphous material, seen to occlude glomerular capillaries, were shown to contain M protein and fibrinogen. Gradual regression of the morphological lesions was observed during the 3 weeks following injection. Initial abnormal proteinuria and azotemia returned to control levels by the end of the 1st week; a second rise in urinary protein excretion and urea retention was demonstrated in some rats coincident with appearance of anti-M antibodies. The mechanism of renal localization of streptococcal M protein by means of a complex with fibrinogen was suggested, which may comprise an initial phase in the pathogenesis of acute poststreptococcal glomerulonephritis

PREPARATION AND ANTIGENICITY OF M PROTEIN RELEASED FROM GROUP A, TYPE 1 STREPTOCOCCAL CELL WALLS BY PHAGE-ASSOCIATED LYSIN

The lysis of Group A type 1 streptococcal cell walls by phage-associated lysin has been described. In the preparation of lysin, a new semisynthetic non-protein media to support growth of the propagating strain of Group C streptococci was employed. Following lysis of the cell walls, the resulting digest was partially purified by ion-exchange chromatography and ammonium sulfate precipitation. In addition to M protein, the resulting preparation (called lysin M protein) contained the group-specific carbohydrate and the T protein—but did not contain antigens, detectable by precipitin tests, which cross-reacted with absorbed heterologous group or type antisera. Capillary precipitin reactions between the lysin M protein and type-specific antiserum did not occur in the presence of high ionic strength buffers; these buffers did not similarly affect precipitin reactions of acid M protein. Type 1 lysin M protein is shown to be a good antigen. A total of 1.5 mg. injected intradermally in saline produced bactericidal antibody in eight of nine rabbits; when injected in adjuvant in one rabbit, protective serum antibodies developed. Streptococci grown in sera from seven of nine rabbits immunized with lysin M protein demonstrated significantly longer chains than when grown in normal rabbit serum. Antibody as demonstrated by each of these three tests was shown to be type-specific. No local or systemic toxicity was noted following intradermal injection in rabbits of lysin M protein

STUDIES ON ARTIFICIAL ANTIGENS : I. ANTIGENICITY OF DNP-POLYLYSINE AND DNP COPOLYMER OF LYSINE AND GLUTAMIC ACID IN GUINEA PIGS

Dinitrophenyl conjugates of poly-L-lysine, varying in percentage conjugation and molecular weight have been found to induce skin reactivity and precipitating antibodies in guinea pigs. At best, 40 per cent of immunized animals developed delayed and immediate responses to DNP-polylysine, which is believed to reflect constitutional differences among the animals assayed. Only those animals capable of responding to DNP-polylysine, responded to an immunologically distinct poly-α-amino acid consisting of glutamyl and lysyl residues ("copolymer glu-lys"). The percentage of animals responding to the DNP-polylysine antigen decreased as the degree of DNP conjugation increased