F. S. Cheever

A possible relationship between viruses of St. Louis encephalitis and epidemic keratoconjunctivitis.

Summary Evidence has been presented which confirms Ruchmans observations that the viruses of St. Louis encephalitis and epidemic keratoconjunctivitis are closely related. The importance of careful study of current outbreaks of epidemic keratoconjunctivitis as a means of assessing the significance of these findings is stressed.

Relation of Viral Proliferation and Antibody Formation in Mice Exposed to Roentgen Radiation.

Summary 1. X-radiation administered prior to Coxsackie virus inoculation increased and prolonged the yield of virus from selected tissues, particularly the pancreas. 2. X-radiation administered prior to virus inoculation inhibited the specific immune response. 3. The deleterious effects of irradiation on antibody formation were not long lasting, in that virus reinoculated 30 days after x-ray exposure evoked a prompt secondary response equal to that of control mice. 4. X-radiation exposure prior to a second inoculation of virus inhibited the secondary response in both the previously irradiated and control mice. 5. These data are compatible with the hypothesis that increased viral proliferation in x-radiated animals is due to the inhibition of the antibody response.

Simian Enterovirus SV2 Hemagglutination Studies. I. Relationship of Infectivity to Hemagglutination.

Summary The hemagglutinating activity for the simian enterovirus SV2 has been shown to be closely related to the infectious virus particle. The time of its appearance in the cell and the period required to reach maximum titer parallel the synthesis of infectious virus. Furthermore, it has the same buoyant density as infectious virus and adsorbs to RBC at the same rate. Exposure to ultraviolet light, and to white light in the presence of neutral red, destroys infectivity without affecting the hemagglutinin. Both properties are quickly destroyed by heat. The authors wish to acknowledge the technical assistance of Miss Mary Ann Sides.

Gamma Globulin Passive Protection Tests in Mice Injected Intraperi-toneally with MEF1 Poliomyelitis Virus.

Summary Suckling mice 5-13 days old were protected against the intraperitoneal inoculation of suckling mouse-adapted MEF1 virus by the intramuscular inoculation of human gamma globulin in amounts as small as 0.05 ml/lb 24 hours prior to the virus challenge. Human gamma globulin in an amount (0.1 ml/lb) adequate to protect against the intraperitoneal inoculation of the suckling mouse-adapted MEF1 virus did not prevent the development of active immunity against the subsequent intracerebral inoculation of Lansing virus.

Characteristics of the growth cycles of four simian enteroviruses (SV2, SV6, SV42, SV49).

Summary A study was made of the rate of adsorption, penetration and multiplication in PMK cell cultures by 4 simian enteroviruses which form different kinds of plaques. The effect of protamine on plaque formation by these viruses was also noted. The results obtained were used to explain differences observed in the size of plaques formed.

Isolation of three unclassified enteroviruses from patients suffering from dysentery.

Summary Three immunologically unrelated enterovirus-like agents, antigenically unrelated to any of the recognized human prototypes were isolated from stool specimens of patients suffering from bacillary dysentery in Mexico City in 1957. The viruses were not pathogenic for suckling mice nor for cultured cells of human origin. Indirect evidence based on antibody studies would indicate that 2 of these viruses may belong to the human enterovirus group. The relationship of these agents to the clinical disease observed remains undetermined.

Virus Isolation Studies of Stool Specimens Obtained from Patients With Cholera.

Summary No evidence has been obtained from the 1959 outbreak of cholera in Bangkok, Thailand that a viral agent played a significant role in the pathogenesis of the diarrheal disease observed. From one patient an enterovirus (Thai C-18) was isolated similar to the Coxsackie A Group of viruses which was not identical with any of the recognized human enteroviruses. Some of the properties of this agent have been described.

Growth of Vaccinia Virus in X-Irradiated Chick Embryo Tissues as Studied in Tissue Culture.

Summary The effect of X-radiation of chick embryonic tissue has been studied in regard to its subsequent ability to support the multiplication of vaccinia virus in tissue cultures. Under the stated experimental conditions radiation of the tissue in vitro had no significant effect; in contrast, exposure of the embryonic tissue to radiation in ovo appeared to diminish its ability to support viral growth in tissue culture. The differences noted were fairly uniform throughout the period studied. Evidence suggesting that the differences noted are due chiefly to secondary radiation effects is discussed.

Propagation of St. Louis Encephalitis Virus in Cells of the Ehrlich Ascitic Tumor of Mice.

Summary The virus of St. Louis encephalitis has been propagated in serial passage in the Ehrlich carcinoma of mice. The optimal conditions for the multiplication of the agent have been determined and relatively high viral titers have been obtained in the ascitic fluid. Some evidence suggesting a slight oncolytic effect has been obtained.

Simian enterovirus SV2 hemagglutination studies. II. Effect of various treatments on the hemagglutinin and its cell receptors.

Summary A study was made of the effect of various chemical, physical and enzymatic treatments on the receptor activity of rhesus RBC and PMK for SV2 virus. The results indicate that the receptors are lipoprotein in nature and similar to one another on both types of cell.