John A. Flick

Use of formalin-treated red cells for the study of influenza A virus hemagglutinating activity.

Human erythrocytes, treated with formalin, the writer has found, retain their ability to react with influenza A virus in a manner quite similar to that of untreated human erythrocytes. For certain types of experiments the use of such formalized red cells possesses distinct advantages over the use of normal red cells. To prepare formalized red cells, equal volumes of a 50% (by volume) suspension of washed red cells in saline and formalin containing sodium chloride in a concentration of 0.85%, were mixed and allowed to stand for 2 to 3 days. If the formalin concentration of the mixture was between 10 and 50%, the cells became dark brown gradually over a period of 24 hours or so. The cells also became cohesive and very resistant to hemolytic agents. The stability of the cells thus treated was marked. Samples of formalized cells stored at 4°C have retained their activity undiminished for influenza A virus for almost two years now. Furthermore, the cells have retained the microscopic appearance and shape of fresh, normal, red cells. Concentrations of formalin of less than 10% (3.6% formaldehyde) in the mixture failed to produce browning of the red cells over 2-3 days at 4°C usually, but did render the cells cohesive. Such cells hemolyzed more readily in hypotonic solutions than did the cells prepared with higher concentrations of formalin. Before using the formalized red cells in reactions with influenza virus the uncombined formaldehyde was removed by repeated washing with saline or water. The cells were allowed to stand in contact with each wash fluid for a period of at least several hours to permit the establishment of an equilibrium between the free formaldehyde inside and outside the cells.

The role of hypersensitivity in the pathogenesis of vaccinia virus infection in humans

To evaluate the role of delayed hypersensitivity in the pathogenesis of the primarysmallpox vaccination reaction, 26 previously unvaccinated children were repeatedly inoculated with vaccinia virus at 2 day intervals. Infectious and noninfectious virus were applied simultaneously at different sites each time. The incubation periods of the papules and the vesicles for the second vaccination were significantly shorter than those of the first. Hypersensitivity to vaccinia virus was apparent within the developmental period of the first vaccination. The shortened incubation period of the second vaccination indicated that delayed hypersensitivity participated in the pathogenesis of the primary lesion.

Elution of Pollen Antigens from Tannic Acid Treated Erythrocytes.

Summary (1) Pollen antigens (short ragweed) elute slowly from the surface of tanned sheep erythrocytes. (2) This elution does not apparently affect the titer obtained over a 2 hr incubation period. (3) Some antigenic fractions fix more permanently than others. (4) The elution is not a function of contact of the RBC-antigen with its specific antibody. (5) This method may possibly be used to separate various antigenic components in the search for antigens with fewer specificities.

The activity of human reagins exposed to the disinfectant, beta-propiolactone

Abstract The viricidal and bactericidal agent, beta-propiolactone, when admixed with serum in a concentration of 0.2 per cent, does not destroy reagins appreciably. The treatment of serum for Prausnitz-Kustner testing with this agent is recommended as a possible safety measure directed especially toward transmission of viral hepatitis. At this time, although there is some evidence from other sources that beta-propiolactone does inactivate hepatitis B virus in serum, the viricidal action of this compound on this particular virus has not been completely elucidated.