פרסומים

The cell-sensitizing factor (SF) of group A streptococci is a teichoic acid which can sensitize mammalian cells to agglutination and lysis in the presence of anti ·SF antibodies and complement. SF is highly immunogenic in the rabbit when bound naturally to some constituent of the streptococcus cell, but only feebly so when it is extracted from the cells by phenol. Both rabbit and human antibodies to SF, which are mainly associated with the macroglobulin fraction (IgM) of serum, are destroyed by treatment with 2-mercaptoethanol. While human anti-SF antibodies are readily destroyed by freezing and thawing and by heating to 58 C, the rabbit anti-SF antibodies are not destroyed at 64 C and are relatively resistant to repeated freezing and thawing. Complexes formed between SF and rabbit antibodies fix complement both in the absence and presence of red blood cells (RBC). Anti-SF antibodies interact with SF and prevent the latter from sensitizing RBC. Rabbits immunized with heat-killed streptococci and which developed anti-SF antibodies, developed severe arthritis when SF was injected into their knee joints. The arthritic lesions were characterized by a marked proliferation of the synovial membrane, a chronic inflammatory exudate and the accumulation of large numbers of lymphocytes in the form of "pseudolymphatic follicles." Nonimmunized animals failed to develop such lesions. It is suggested that sensitization of cells with SF during streptococcal infection may lead to passive immune cytolysis and may thus contribute to the pathogenicity of streptococci.

The production of extracellular nicotinamide adenine dinucleotide glycohydrolase (NADG) and the cell-bound lipoproteinase (serum opacity reaction, SOR) by strains of different serological types of group A streptococci, in relation to the T typing, was studied. The production of both NADG and SOR, or only one of them, was found to be characteristic of serotypes, as determined by M and T antigen. No difference in the production of these enzymes was found in relation to M-positive and M-negative variants. Investigation into NADG and SOR production as related to the T type enabled the division of a single agglutination pattern into four main groups, each of which corresponds to one specific M type or more. Of the 370 strains belonging to 12 different T-agglutination patterns, 21% produced both enzymes and 42.5% failed to produce any of them, whereas the remaining 36.5% produced only one out of the two enzymes. Five streptococcal types which did not produce NADG and SOR also failed to synthesize streptolysin S at the early logarithmic phase of growth, indicating that streptolysin S production by young cultures may be also related to serotype. No correlation was found between the production of NADG-SOR as related to serotype and the production of streptolysin O, acid phosphotase, esterase, N-acetylglucosaminidase, hyaluronidase, streptokinase, and the cell-sensitizing factor. The practical and potential usefulness of NADG and SOR production in epidemiological studies is discussed.

Washed suspensions of group A, C, and G streptococci and group A L-forms possess phosphatase, esterase, and N-acetylglucosaminidase, respectively. Cell-free extracts, obtained from streptococci and Informs by mechanical disintegration or by treatment of group A streptococci with phage-associated lysin, possess, in addition to these enzymes, an adenosine triphosphatase (ATPase). Over 90% of the total ATPase and NAGAase and 50% of phosphatase and esterase activities were solubilized by cell breakage, indicating that the latter 2 enzymes are membrane-bound. A partial separation between the phosphatase, NAGAase, and ATPase was achieved by gel filtration of cell-free extracts on Sephadex G-200. Phosphatase was eluted with high molecular weight material excluded from the column. NAGAase and ATPase were associated with much lower molecular weight fractions, while esterase activity was present in both high and low molecular weight fractions. Studies on substrate specificity showed that fractions which split PNP-phosphate also split PNP-acetate and PNP-propionate fractions which split ATPase also split CTP, ITP, and GTP but to a lesser extent. Fractions which were active against β-napthylacetate also split β-naphthyl butyrate (15% efficiency); no activity against longer fatty acid esters of PNP or β-naphthyl derivatives was present.