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C R Stokes

Publications and source records attributed to C R Stokes.

152 records · Page 9Linked to original sources
PubMed1975

Isolation and characterization of cal allergens.

A crude (saline soluble) extract of cat skins capable of eliciting a strong positive prick skin test in cat sensitive individuals was fractionated on Sephadex G200. Active fractions were pooled and successively fractionated on isoelectric focusing gradients of pH 3-5 and pH 4-5. Allergenic activity was localized in two peaks with mean isoelectric points of 4-1 and 4-35 respectively. On immunoelectrophoresis the allergen with pI = 4-35 was associated with a protein which was subsequently found to be immunologically indistinguishable from serum albumin and to have a molecular weight of 69,000 daltons. The allergen with pI = 4-1 migrated in the alpha2-region on immunoelectrophoresis and had a mean molecular weight of 55,000 daltons. This allergen was isolated and analysed for amino acid and carbohydrate content. A combined extract of both allergens coupled to microcrystalline cellulose and used a RAST procedure readily distinguished between two groups of individuals classified as skin test positive and skin test negative to cat allergen.

Allergens↗
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The humoral and cell mediated immune response of young chicks to Salmonella typhimurium and S. Kedougou.

Day old chicks were inoculated with either Salmonella typhimurium or S. Kedougou as representative examples of an invasive and a non-invasive strain respectively. The titres of IgA, IgG and IgM antibodies were determined, using an enzyme-linked immunosorbent assay (ELISA) in the bile, serum and homogenates of intestinal mucosa each week up to 5 weeks of age. Statistically significant increases in antibodies were detected in the bile (IgA and IgG) and the intestinal mucosa and serum (IgG and IgM) 1 week after the birds were inoculated with S. typhimurium. In contrast, only a limited response was recorded for S. kedougou 4 weeks after challenge commenced. The birds appeared capable of eliminating systemic infection with S. typhimurium as they grew older although a cell mediated immune response was demonstrated in less than half the birds aged 4 or 5 weeks. The demonstration of only a limited serological response to S. kedougou indicates that serological testing may have a limited role in monitoring flocks for infection with non-invasive serotypes.

Animals↗
PubMedDate not supplied

The distribution of leucocyte subsets in the small intestine of healthy cats.

The aim of this study was to investigate the distribution of leucocyte subsets in the small intestine of healthy adult cats (n=16). Immunohistochemical methods were used to identify leucocyte subsets within the mucosa of the duodenum, jejunum and ileum. Computer-aided morphometry was used to enumerate cells within the epithelial compartment, villous lamina propria and lamina propria adjacent to upper and lower crypt. Throughout the small intestine, IgA+ and IgM+ plasma cells were more prominent in the lamina propria adjacent to the lower crypt than in the villus, whereas IgG+ plasma cells were present in equal numbers in the crypt and villous regions. Overall, IgA+ plasma cells predominated and IgM+ plasma cells were higher in number than IgG+ plasma cells at each of the three anatomical locations. By contrast, T cells (CD3+) and T-cell subsets (CD4+ and CD8+) were present in greater numbers in the villous lamina propria than in the lamina adjacent to the crypts. Intraepithelial lymphocytes (IELs) were also characterized phenotypically, the majority being CD8+ T lymphocytes. Lamina propria macrophages and dendritic cells were characterized by expression of L1 and major histocompatibility complex (MHC) class II, and MHC class II expression by enterocytes overlying Peyer's patches, although rare, was also shown. The qualitative and quantitative data from this study provide a basis for comparison with cats with inflammatory enteropathies.

Animals↗
PubMedDate not supplied

Experimental Microsporum canis infection in cats: correlation between immunological and clinical observations.

Microsporum canis infection was induced in five of six adult cats by the application of mycelium to shaved and mildly abraided skin. The clinical course of the disease was monitored over 16 weeks by physical examination and Wood's lamp illumination. The incubation period (time from inoculation to first appearance of infected hairs) varied between 8 and 13 days and was followed by a progressive phase of slow peripheral expansion of lesions accompanied by scaling, alopecia and skin thickening that lasted for approximately 2 weeks. In four of the five cats the lesions then remained stable for between 1 and 6 weeks before regression occurred, with clinical resolution evident in these cats by 11-14 weeks post-infection. In one cat disease was more prolonged, with regression only beginning at the end of the study, and this cat also developed a satellite lesion. Immunological responses during infection were monitored every 2 weeks and consisted of ELISA to measure serum M. canis-specific IgG, IgM and IgA antibody concentrations, M. canis antigen-specific lymphocyte proliferation assay, and mitogen-induced (ConA) lymphocyte proliferation assay. In all three immunoglobulin classes evaluated, a significant (P < or = 0.020) rise in antibody concentration was seen in response to infection, and occurred earliest with the IgM class (2 weeks post-infection). Overall, a heterogeneous antibody response was found, and changes in antibody concentration showed no clear temporal relationship to recovery from disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗