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Analysis of Simian Immunodeficiency Virus-specific CD8+ T-cells in Rhesus Macaques by Peptide-MHC-I Tetramer Staining
Published on: December 23, 2016
Serological responses of cats to feline immunodeficiency virus
Abstract:
The proteins of feline immunodeficiency virus (FIV) were identified by sodium dodecylsulphate poly-acrylamide gel electrophoresis (SDS-PAGE) and immunoblotting. Purified [35S]methionine/cysteine-labelled virus contained proteins of Mr 120, 24, 17, and 10kD, of which the most prominent were p24 and p17, and minor components of 62, 54, 52, 41 and 32kD. Sera from FIV-infected cats precipitated two glycoproteins (gp) of Mr 120kD (gp120) and 41kD (gp41) from lysates of [14C]glucosamine-labelled infected cells. Purified virus contained very little or no detectable glycoproteins. The serological response to individual viral proteins was followed in experimentally infected cats by immunoblotting. Since purified virus was a poor source of gp120, a method using FIV-infected cell lysates was developed. Cats produced antibodies to gp120, p55, p24 and p17. (The p55 was presumed to be a precursor of p24 and p17.) Following infection, antibodies developed first to p24 and subsequently to p17, p55 and gp120. Sera from cats infected with three separate isolates of FIV, two from the UK and one from the USA, had cross-reacting antibodies to all of these viral proteins. The criteria for identification of seropositive cats were defined. The minimum requirement for a positive immunoblot was antibody to gp120 or to at least three core proteins (p55, p24 and p17). Comparison of two commercial enzyme-linked immunosorbent assay (ELISA) kits and immunoblotting indicated that false-positive results occurred as a result of non-specific reactions in the ELISA systems.
Insights
Researchers identified feline immunodeficiency virus (FIV) proteins using SDS-PAGE and immunoblotting. Cats developed antibodies to FIV glycoproteins (gp120) and core proteins (p24, p17), aiding seropositive cat identification.
Area of Science:
- Virology
- Immunology
- Biochemistry
Background:
- Feline immunodeficiency virus (FIV) is an important pathogen in cats.
- Understanding FIV protein structure and host immune response is crucial for diagnostics.
Purpose of the Study:
- To identify FIV viral proteins.
- To characterize the serological response to FIV proteins in infected cats.
- To establish criteria for identifying seropositive cats.
Main Methods:
- Sodium dodecylsulphate poly-acrylamide gel electrophoresis (SDS-PAGE) and immunoblotting.
- Metabolic labeling of FIV with [35S]methionine/cysteine and [14C]glucosamine.
- Analysis of sera from experimentally infected cats.
Main Results:
- Prominent FIV proteins identified: p24 and p17. Glycoproteins gp120 and gp41 were detected in infected cell lysates but not in purified virus.
- Cats produced antibodies against gp120, p55 (precursor), p24, and p17.
- Antibody development followed a sequence: p24, then p17, p55, and gp120.
- Cross-reacting antibodies were observed across different FIV isolates.
- Defined criteria for seropositive identification: antibody to gp120 or at least three core proteins (p55, p24, p17).
- Commercial ELISA kits showed false-positive results due to non-specific reactions.
Conclusions:
- Immunoblotting is effective for identifying FIV proteins and assessing host immune response.
- Established serological criteria aid in accurate diagnosis of FIV infection.
- Caution is advised with commercial ELISA kits due to potential non-specific reactions.
