Heterogeneity in cellular and humoral immune responses against Toxoplasma gondii antigen in humans

• Published in: Clinical and experimental immunology Vol. 136; no. 3; pp. 535 - 541
• Main Authors: FATOOHI, A. F., COZON, G. J. N., GONZALO, P., MAYENCON, M., GREENLAND, T., PICOT, S., PEYRON, F.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.06.2004; Blackwell; Oxford University Press; Wiley; Blackwell Science Inc
• Subjects: Animals; Antibodies, Protozoan - immunology; Antigens, Protozoan - blood; Antigens, Protozoan - immunology; Biochemistry, Molecular Biology; Biological and medical sciences; Blotting, Western - methods; Case-Control Studies; CD25; CD4-Positive T-Lymphocytes - immunology; cellular response; Clinical Studies; Electrophoresis, Gel, Two-Dimensional; Female; Flow Cytometry; Human protozoal diseases; Humans; humoral response; Infectious diseases; Life Sciences; Lymphocyte Activation; Medical sciences; Parasitic diseases; Pregnancy; Protozoal diseases; Receptors, Interleukin-2 - immunology; Toxoplasma - immunology; Toxoplasma gondii; Toxoplasmosis; Toxoplasmosis - immunology; Human; Protozoa; Immunopathology; Apicomplexa; Protozoal disease; Immune response; Cellular immunity; Parasitosis; Infection; Antigen; Heterogeneity; Immunology; Toxoplasma gondii; cellular response humoral response Toxoplasma gondii CD25; Toxoplasmosis; Humoral immunity
• ISSN: 0009-9104; 1365-2249
• DOI: 10.1111/j.1365-2249.2004.02466.x

ABSTRACT Protection against Toxoplasma gondii in infected patients is mainly attributed to cellular immunity. We here attempt to improve the characterization of the proteins that induce cellular immunity in naturally infected patients. Cellular immunity was evaluated by flow cytometry after 7 days of blood culture from 31 chronically T. gondii infected and 8 noninfected pregnant women, in the presence of soluble T. gondii antigen (ST‐Ag) or fractionated proteins from ST‐Ag, separated by sodium dodecyl sulphate polyacrylamide gel electrophoresis. Blood cultures from infected patients with ST‐Ag induced 39·5 ± 12·7% of activated (CD25+) CD4+ T cells using flow cytometry. This contrasts with the absence of activated CD4+ T cells after either culture with PBS or in blood cultures from noninfected women. The protein fraction between 21 and 41·9 kD induced the highest response (14·7 ± 10·0%). Blood samples from 20 infected  and  5  uninfected  women  were  cultured  in  presence  of  12  protein  subfractions  of  2–208 kD. The highest frequencies of response among infected patients were seen with fractions (Fr) 26–31·9 kD (C.I. 85–100%) and Fr 32–36·9 kD (C.I. 77–100%). Although we note a good concordance between cellular and humoral response, Western blot analysis of ST‐Ag does not completely predict the panel of proteins recognized by cellular immunity. Two‐dimensional separation of the ST‐Ag revealed more than 200 protein spots in these fractions. However, only two proteins in the 20–40 kD range induced a significant humoral response. Further studies are necessary to determine which proteins in the Fr 26–31·9 kD and 32–36·9 kD are superior immunogens for cellular responses.