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S Baron

Publications and source records attributed to S Baron.

305 records · Page 17Linked to original sources
PubMedDate not supplied

Characterization of an antiviral agent from primary murine fibroblast cultures: murine tissue culture CVI.

We have previously described a class of virus inhibitors which are produced spontaneously by many types of cells in culture and present in a number of physiological fluids. These inhibitors are differentiated from all other known naturally occurring antiviral substances in regard to their (i) lack of species specificity, (ii) broad antiviral activity (iii) absence of high affinity binding by the inhibitor to the virus, (iv) mechanism of the action of the inhibitor is through inhibition of viral attachment, and (v) extreme thermal stability. In this report, we show that this class of inhibitors can be divided into two distinct subclasses. The first category includes the inhibitor spontaneously produced by cells in culture, originally described as contact-blocking viral inhibitor (CVI), and has a polypeptide component associated with its antiviral activity. The second category includes the inhibitors detected in body fluids and tissue extracts and has no essential peptide structure. Further characterization of CVI with respect to molecular size and stability to heat and a number of chemical reagents and enzymes indicate that the antiviral activity of CVI is associated with a large molecule (90s or approximately 4 million daltons), is stable at 100(8)C, and is resistant to the action of RNase, DNase, sulfhydral reagents, protein denaturants, and extraction by organic solvents.

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PubMedDate not supplied

Induction of interferon by bacteria, protozoa, and viruses: defensive role.

Interferon is established as one of the natural defenses against virus infection. The evidence that interferon may serve a defensive role against certain protozoa is less complete and consists mainly of induction of interferon during protozoal infection, as well as interferon protection of mice against malarial infection. The evidence that interferon may function as a defense against certain bacterial infections is extended with data indicating that a wide variety of bacteria can induce interferon in the mouse and in cultured human peripheral lymphoid cells. This induction of interferon by bacteria and the ability of interferon under many conditions to activate neutrophils and macrophages raises the possibility that interferon may serve a defensive role against some bacteria.

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PubMedDate not supplied

Transmission of IFN-induced activities by cell to cell communication.

In conclusion, many of the activities of IFN are transmissible between cells and may involve more than one transfer mechanism. These mechanisms probably involve secondary messenger molecules which are shared with hormones and act at the transcriptional level. The transfer system seems to be a major amplification process for IFN action. It will be interesting in the future to determine the spectra of IFN activities which are transferable as well as the processes involved.

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PubMedDate not supplied

[Epidemiology of pertussis in industrialized countries].

Pertussis remains present in the industrialized world, although the widespread use of whole-cell pertussis vaccine has led to a dramatic decline of the disease. Great differences in immunization policies and coverage explain the uneven epidemiological pattern across the developed world. Different situations can be described. In some countries such as Japan, UK and Italy, concerns about the occurrence of severe adverse events following pertussis vaccination in the 70's led to a reduced acceptance and thus, to a significant decrease in immunization coverage. In Sweden, the protective efficacy of pertussis vaccine was questioned and vaccination was discontinued in 1979. In all these countries, severe epidemics of pertussis were observed in the following years, and immunization was then reinforced in some (UK). In Japan, considerable efforts were made to develop new and safer pertussis acellular vaccines which have replaced the whole-cell vaccine since 1981. In other countries such as the USA and France, despite a continuous immunization programme maintaining a sustained and high coverage, a resurgence of the disease was observed in association with a modification of the age-distribution. Vaccinated adults became susceptible to the infection because of progressive waning, vaccine-induced immunity. These patients contaminated very young and thus, unvaccinated infants. These observations underline the need for early immunization in infants as well as the importance of late booster doses to be given to older children or adults.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Generalized occurrence of the broadly antiviral substance UTI beta in mammalian sera.

This study compares the characteristics of naturally occurring antiviral activities in nonhuman mammalian sera to UTI beta (University of Texas virus inhibitor beta), an innate, non-specific viral inhibitor found in human serum. The antiviral agent in sera from four different species appears to possess properties similar to those of UTI beta, e.g. molecular weight of 60 +/- 10 kDa, broad spectrum antiviral activity, glycoprotein structure with antiviral oligosaccharide moiety(s) attached to a carrier protein, and inhibition of most viruses by preventing their attachment to target cells. These findings suggest that UTI beta or UTI beta-like virus inhibitors are a normal component of the non-specific immune defenses of mammals.

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