3T3 cells do not grow in Methocel suspension culture, while other permanent cell lines do. The viability of 3T3 cells in suspension remains unchanged for at least three days with respect to plating efficiency, vital staining and resumption of normal growth when transferred into monolayer culture. When monolayer 3T3 cells in G1 phase are suspended they remain in G1 phase. Cells already in S phase which are suspended complete ongoing DNA synthesis and mitosis and then are arrested in the G1 phase. Progress through the cell cycle is reinitiated after suspended cells attach to a surface. When monolayer cells in late G1 phase (just before entering S phase) are put in suspension cultures they do not initiate DNA synthesis.

Separation and properties of a red cell sensitizing substance from streptococci. J. Bacteriol. 91:2200-2204. 1966.-An antigen that binds onto red cells and causes them to be agglutinated by antiserum was separated from streptococci. Various procedures to extract the antigen from streptococci were investigated, and the greatest amount of antigen was obtained by extraction of cells with a phenol-water mixture. The reaction of the antigen with red cells was shown to be reversible by use of the Ashby mixed agglutination technique. The antigen also combines with a number of different tissues, and it was demonstrated that the antigen could be transferred from red cells to tissues and vice versa. An hypothesis is presented on the basis of these findings which suggests a possible role for this antigen in the etiology of rheumatic fever.

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