Joseph P. Schaller

Influence of culture conditions on growth of FL-74 cells and feline oncornavirus cell membrane associated antigen production

SummaryThe FL-74 cell, a feline lymphoblastoid cell line derived from a tumor induced by leukemia virus, grows equally well in static suspension culture (plastic T-flask or silicone treated glass bottles) or in spinner culture. No growth was observed in unsiliconized glass bottles. Although feline leukemia virus production was nearly the same in FL-74 grown in each of the above types of vessel, the expression of the feline oncornavirus membrane associated antigen (FOCMA), as determined by membrane immunofluorescence, was more intense and more complete on cells grown in static suspension. Moreover, higher fluorescent antibody titer endpoints were observed with cells from static suspension cultures than with cells from spinner cultures. FL-74 cells grown in spinner culture, when subjected to partial synchrony by cold block or by deprivation of essential amino acids (arginine and/or isoleucine) for 12 hr, achieved a membrane fluorescent pattern for FOCMA similar to celsl grown in static suspension. It is proposed that the expression of FOCMA on the cell membrane surface is cell-cycle dependent, and that the rate at which a cell passes through the cell cycle determines the pattern and intensity of the fluorescence of the cell membrane.

Passive Immune Protection from Diarrhea Caused by Rotavirus or E. Coli: An Animal Model to Demonstrate and Quantitate Efficacy

Several studies have described the use of orally administered passive antibodies from heterologous species origin to control enteric disease caused by bacteria1–4, viruses5–13, and protozoa14. Both the therapeutic and prophylactic properties of passive antibodies have been evaluated. The therapeutic efficacy has been confined to suppressed pathogen shedding with limited effects reported on the acute clinical disease2,12. The reported lack of therapeutic effect on the course of the Escherichia coli and rotavirus diarrhea episodes may be attributed to the self-limiting nature of these diarrheas in healthy patients. Passive antibody is effective in treating Cryptosporidium infection14 and may also be effective in treating chronic diarrhea in immunocompromised patients.