TREPONEMA PALLIDUM HAEMAGGLUTINATION TEST (TPHA) Syphilis is a complex disease which is normally sexually transmitted. The causative organism, Treponema pallidum cannot be grown on conventional laboratory culture media or in the tissue culture. Infection is normally diagnosed by directing antibodies specific for T. pallidum in the patient’s serum or CSF. Antibody becomes detectable at about 3-4 weeks following exposure, and may remain at detectable levels for long periods after treatment. Two groups of antibodies are formed: one reacting with the non-treponemal antigens used in the VDRL / Carbon antigen and RPR tests, and the other reacting with the specific antigens of T. pallidum. Antibody to non-treponemal antigens is found (normally) in active disease and the levels subside after successful treatment. Specific antibody persists long after the infection has been successfully treated. It is necessary to test for both groups of antibody since the non-treponemal antibody may arise for reasons other than Syphilitic infection. TPHA is a specific, sensitive passive haemagglutination test for the detection of antibodies to Treponema pallidum in serum or CSF. Principle: TPHA comprises T. pallidum sensitized, formolised, tanned fowl erythrocytes; unsensitized, formolised, tanned fowl erythrocytes; diluent and control sera. When diluted positive samples are mixed with sensitized erythrocytes, antibody to the sensitizing antigen causes agglutination of the cells. The cells form a characteristic pattern of cells in the bottom of a microtitration plate well. In the absence of antibody, they form a compact button in the well. Questions 1. Is the TPHA test specific for Treponema pallidum? 2. Create an illustration showing a passive haemagglutination reaction 3. Discuss how Syphilis causes disea

Principles Of Pharmacology Med Assist

6th Edition

ISBN:9781337512442

Author:RICE

Publisher:RICE

Chapter14: Allergy: An Overview

Section: Chapter Questions

Problem 24RQ

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TREPONEMA PALLIDUM HAEMAGGLUTINATION TEST (TPHA) Syphilis is a complex disease which is normally sexually transmitted. The causative organism, Treponema pallidum cannot be grown on conventional laboratory culture media or in the tissue culture. Infection is normally diagnosed by directing antibodies specific for T. pallidum in the patient’s serum or CSF. Antibody becomes detectable at about 3-4 weeks following exposure, and may remain at detectable levels for long periods after treatment. Two groups of antibodies are formed: one reacting with the non-treponemal antigens used in the VDRL / Carbon antigen and RPR tests, and the other reacting with the specific antigens of T. pallidum. Antibody to non-treponemal antigens is found (normally) in active disease and the levels subside after successful treatment. Specific antibody persists long after the infection has been successfully treated. It is necessary to test for both groups of antibody since the non-treponemal antibody may arise for reasons other than Syphilitic infection. TPHA is a specific, sensitive passive haemagglutination test for the detection of antibodies to Treponema pallidum in serum or CSF. Principle: TPHA comprises T. pallidum sensitized, formolised, tanned fowl erythrocytes; unsensitized, formolised, tanned fowl erythrocytes; diluent and control sera. When diluted positive samples are mixed with sensitized erythrocytes, antibody to the sensitizing antigen causes agglutination of the cells. The cells form a characteristic pattern of cells in the bottom of a microtitration plate well. In the absence of antibody, they form a compact button in the well. Questions 1. Is the TPHA test specific for Treponema pallidum? 2. Create an illustration showing a passive haemagglutination reaction 3. Discuss how Syphilis causes disea

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