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Biomedical subjects

C R Rossi

Publications and source records attributed to C R Rossi.

At least 91 records · Page 5Linked to original sources

Bovine peripheral blood monocyte cultures: growth characteristics and cellular receptors for immunoglobulin G and complement.

Bovine peripheral blood monocytes were cultured in vitro for as long as 60 days. Although mitotic figures were not observed, the amount of cytoplasm was observed to increase; most cultures developed multinucleated cells, some containing as many as 200 nuclei. In multinucleated cells, the nuclei were peripherally distributed around a cytoplasmic matrix and surrounded by an undulating membrane. Receptors on macrophages were identified with erythrocytes sensitized with various immunoglobulins and complement (C'). A receptor for immunoglobulin G, but not immunoglobulin M, was detected. By the use of freshly prepared equine serum, a C' receptor was detected; however, by the use of freshly prepared bovine serum, C' receptor was not detected.

Animals↗

Bovine immunoglobulin G subclass receptor sites on bovine macrophages.

Macrophage cultures were initiated from bovine peripheral blood monocytes. The following antiserums were prepared: rabbit immunoglobulin (Ig) M anti-sheep erythrocyte (RBC) serum, bovine IgG1 anti-rabbit Ig serum, and bovine IgG2 anti-rabbit Ig serum. Erythrocytes treated singly with any of these serums failed to mediate attachment of RBC to macrophages. Erythrocytes treated with rabbit IgM anti-sheep RBC serum followed by either bovine IgG 1 or IgG2 anti-rabbit Ig serum attached to bovine macrophages, as seen microscopically. Results indicate that bovine macrophages contain receptors for both bovine IgG subclasses.

Animals↗

Antibody class and complement requirement of neutralizing antibodies in the primary and secondary antibody response of cattle to infectious bovine rhinotracheitis virus vaccine.

Calves responded to a single intramuscular injection of an attenuated strain of infectious bovine rhinotracheitis virus by producing IgM followed by IgG antibody. Both IgM and IgG antibody produced during the first month were primarily complement-requiring neutralizing antibody (CRNAb), especially IgM antibody. After a month, IgG had replaced IgM as the predominant immunoglobulin, and titers with and without complement (C') decreased in both IgG and IgM fractions. The largest decrease was in the IgM CRNAb fraction. Seven days after a second injection given on day 196, calves responded with an anamnestic IgG response in which CRNAb titers were 1 or 2 two-fold dilutions higher than non-CRNAb titers. One calf developed an IgM response similar to its primary response, whereas inhibition of the IgM response occurred in the other 3 calves which had much lower IgM antibody titers than those attained in the primary response. Twenty-eight days after the second injection the titers of IgG were the same or only a 2-fold dilution less than their 7-day secondary titers, whereas IgM titers generally decreased considerably more than this. Guinea pig and rabbit sera were equally effective as C' sources in potentiating CRNAb, whereas bovine serum was a poor C' source.

Animals↗

Immunoglobulin concentrations and bovine enterovirus inhibitors in fetal bovine fluids.

Fluids from 53 bovine fetuses ranging in age from 90 to 240 days were examined for immunoglobulin G (IgG) and immunoglobulin M (IgM) and neutralizing activity to ten bovine viruses. Non-specific inhibitors to bovine enteroviruses were found in serum, allantoic, and amniotic fluids of most samples tested. In most cases, serum IgG were within normal values. Neither IgG nor IgM was detected in amniotic fluids, whereas 2 samples of allantoic fluid contained traces of IgG.

Allantois↗

Antibody to viruses affecting cattle in commercial tissue culture grade fetal calf serum.

Commercial fetal calf serum (FCS) for tissue culture use was tested for neutralizing activity against several viruses which affect cattle. Certain lots of FCS contained no neutralizing activity, whereas other lots contained neutralizing activity to several viruses. It was concluded that the neutralizing activity found in certain lots of sera was due to specific antibody and that its presence could be most easily explained by the contamination of the FCS with serum from postcolostral bovine serum. A nonantibody inhibitor to vesicular stomatitis virus was also found at low levels in most lots of serum. Because those sera which had antibody had antibody to several viruses, it was suggested that the use of the micro-serum neutralization test with a few bovine viruses which are widespread in the bovine population should be satisfactory to detect FCS which was contaminated with postcolostral bovine serum.

Adenoviridae↗

Serological evidence for the association of bovine respiratory syncytial virus with respiratory tract disease in Alabama cattle.

A serological investigation for neutralizing antibody to bovine respiratory syncytial virus (BRSV) was conducted using an antigenically related human strain of respiratory syncytial virus. Results demonstrated the effectiveness of the procedure. Sixty-seven percent of healthy, adult cattle tested were found to have antibody to BRSV. Calves in several herds were exposed to conditions to encourage development of respiratory tract disease. In three herds in which respiratory tract disease subsequently developed, the incidence of BRSV seroconversions approached 100%. In a herd in which no respiratory tract disease was detected, BRSV seroconversions indicated a high incidence of subclinical infections. It was concluded that, in this country as has been shown in others, BRSV is probably a significant pathogen of the bovine respiratory tract.

Alabama↗