Human Conjunctival Cells Research Articles

Cell-Mediated Immune Response to Mumps Virus Infection in Man

The antibody and cell-mediated immune response to mumps virus infection was studied in groups of subjects after natrually acquired mumps virus infection, after parenteral immunization with live attenuated mumps vaccine, and in a population of mumps seronegative subjects. The technique of neutralization of tissue culture infectivity was utilized to study mumps specific antibody. The cell-mediated immunity (CMI) was detected by specific immune release (SIR) of radioactivity by purified lymphocytes after they were reacted with radioactive chromium (51Cr) labeled human conjunctival cell cultures chronically infected with mumps virus. No SIR activity was observed in lymphocytes obtained from cord blood and young individuals seronegative for antibody to mumps virus. Detectable SIR activity was observed in a few older seronegative subjects; however, immunization with mumps vaccine in such antibody negative subjects failed to result in the development of any antibody response in the serum. High SIR activity was observed in the lymphocytes of naturally infected and vaccinated subjects. Although all naturally infected or immunized subjects had varying levels of mumps specific antibody activity in the serum, no correlation existed between the levels of antibody and SIR activity. These observations suggest the development of mumps specific in vitro correlates of CMI after naturally acquired or vaccine-induced mumps virus infection.

Plaque formation by clinical isolates of influenza A2-Hong Kong.

Human conjunctival cell variant (clone 1-5C-4) has been previously shown to be the only established cell line to support plaque formation by laboratory strains of influenza viruses. The present study describes characteristic plaque formation in clone 1-5C-4 by unadapted clinical isolates of influenza A2/Hong Kong. It is concluded that this technic may provide an additional diagnostic tool for clinical virology laboratories.

Genetic recombination between influenza viruses Ao-NWS and A2-Hong Kong.

Genetic cross was performed in human conjunctival cell cultures between two strains of influenza A virus, Ao/NWS and A2/Hong Kong, both of which plaque with high efficiency on the above cells and which differ from each other in some genetic markers. Clones of progeny virus from mixed infection were isolated in the absence of selective procedures and individually tested for the following marker characteristics; the serotype of the hemagglutinin and the neuraminidase, plaque size, plaque forming capability on FL cells, and requirement of DEAE-dextran for plaque formation. Characterization of 42 clones showed the recombination frequency in two factor cross between the above markers ranged from 18 to 43%. There was no indication of linkage between the markers employed. From the absence of recombination within the serotype of the hemagglutinin or that of the neuraminidase, it was suggested that recombination occurs mainly by exchange of cistrons. Three clones were suspected to be initiated by partially heterozygous virus particles.

The effect of actinomycin D on the synthesis of influenza virus-specific RNA.

The effect of actinomycin D on the replication of CAM strain of influenza A1 virus was studied in the human conjunctival cell line, clone 1-5C-4. Actinomycin D in a concentration of 0.5 mcg/ml suppressed the virus yield to less than l/1000th of that from the uninhibited culture. When the addition of actinomycin D was delayed, the resistance of the production of virus and viral components to actinomycin D developed progressively in the order of the soluble antigen, hemagglutinin, and the infective virus. The synthesis of virus-specific RNA was demonstrable by the incorporation of tritiated uridine when actinomycin D was added to the culture at 6 hours after infection, but not when it was added at 1 hour after infection. These findings indicated that actinomycin D illhibits influenza virus replication because it inhibits the synthesis of virusspecific RNA and that, however, it does not directly block virus-specific RNA synthesisper se but exerts the inhibitory effect on some event(s) preceding virus-specific RNA synthesis. In FL cells, in which CAM virus undergoes an abortive multiplication cycle, virus-specific RNA was synthesized in the same period after infection and in a similar quantity as in clone 1-5C-4 cells in which complete multiplication occurs.

Changing viral susceptibility of a human cell line in continuous cultivation. I. Production of infective virus in a variant of the Chang conjunctival cell following infection with swine or N-WS influenza viruses.

During its serial transfer and cultivation in this laboratory, a human conjunctival cell line (Chang) was observed to change in morphology. Concurrently no change was noted in the susceptibility of the cells to viruses capable of infecting the original cell line. However, it was noted that the derived variant cell line had acquired susceptibility to the induction of cytopathic effects and incomplete virus formation by several strains of influenza viruses. It was then discovered that swine influenza virus and the N-WS strain of influenza A virus could be serially propagated in the derived cell line with production of infective virus. The swine virus required adaptation, but the N-WS strain did not. N-WS and swine influenza viruses multiply with infective virus formation only in the variant conjunctival cell and in no other cell line. Antigenic, cytologic, and virologic evidence is presented that the influenza virus-susceptible variant cell is of human origin and is not a contaminating cell exogenously introduced. Transition of a cell line from complete insusceptibility to susceptibility to virus infection and multiplication has not been described previously.

Triglyceride Utilization by Human HeLa and Conjunctiva Cells in Tissue Culture

Two types of fat emulsions have been studied in tissue culture of human HeLa and conjunctival cells. Soybean phosphatides or a synthetic material (Pluronic-F68) was used as the emulsifying agent. Cell multiplication was unaffected by the presence of Pluronic-stabilized emulsions and appeared to be somewhat decreased with a 2 per cent phosphatide-stabilized emulsion. Emulsions of glyceryl triolein-1-C14 and glyceryl tripalmitin-1-C14 were converted to C14O2 by both kinds of cells.

Bicarbonate as an essential for human cells in vitro

Human conjunctival and Hela cells were grown in vitro in the presence or absence of HCO 3 −. In the presence of HCO 3 −, multiplication of both cell strains was rapid; whereas, in its absence, a decrease in the number of cells was found. Such a decrease was small if the medium was changed on alternate days, presumably because of transient exposure of the cells to CO 2. At any time studied up to 14 days, cell multiplication was restored by the addition of HCO 3 − to the medium.

Isolation of nutritional variants from conjunctival and HeLa cells.

SummaryA method used successfully in isolation of nutritional variants from the human conjunctival and HeLa cells has been described. Variants capable of continuous propagation, under prescribed experimental conditions, with d (+) xylose, d-ribose or sodium lactate as the sole source of added carbohydrate or intermediate have been isolated.

Meso-inositol requirement of HeLa and human conjunctival cells.

SummaryA concentration of meso-inositol of at least 4 μM was necessary for maximum multiplication of human conjunctival cells grown in vitro. Inositol was found to be essential for multiplication of HeLa cells.