Práctica 1, Ejercicios de Endocrinología

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Exercise 12: Serological Testing: Activity 1: Using Direct Fluorescent Antibody Technique to Test for Chlamydia Lab Report

Pre-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly.

1. Which of the following has an epitope? You correctly answered: b. an antigen
2. Chlamydia trachomatis is You correctly answered: c. a bacterium that reproduces inside its host cell.
3. The infectious form of Chlamydia that is spread from person to person is the You correctly answered: d. elementary body that stains green in this activity
4. The goal of the direct fluorescent antibody test is to test for the presence of You correctly answered: c. antigen.

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Experiment Results Stop & Think Questions: The source of the patient samples is You correctly answered: c. epithelial scrapings

What is the name for the specific part of the antigen that the antibody binds to? You correctly answered: b. epitope

15. Drag the first slide (patient A) to the fluorescent microscope.

Count the number of elementary bodies you see through the microscope (recall that elementary bodies stain green), enter the number of elementary bodies in the field below, and then click Submit to display your results in the grid. After you click Submit , the slide will automatically be placed in the biohazardous waste disposal. You answered: 0 elementary bodies

16. Drag the next slide (patient B) to the fluorescent microscope.

Count the number of elementary bodies you see through the microscope (recall that elementary bodies stain green), enter the number of elementary bodies in the field below, and then click Submit to display your results in the grid. After you click Submit , the slide will automatically be placed in the biohazardous waste disposal. You answered: 17 elementary bodies

17. Drag the next slide (patient C) to the fluorescent microscope.

Count the number of elementary bodies you see through the microscope (recall that elementary bodies stain green), enter the number of elementary bodies in the field below, and then click Submit to display your results in the grid. After you click Submit , the slide will automatically be placed in the biohazardous waste disposal. You answered: 1 elementary bodies

18. Drag the next slide (positive control) to the fluorescent microscope.

Count the number of elementary bodies you see through the microscope (recall that elementary bodies stain green), enter the number of elementary bodies in the field below, and then click Submit to display your results in the grid. After you click Submit , the slide will automatically be placed in the biohazardous waste disposal. You answered: 19 elementary bodies

19. Drag the last slide (negative control) to the fluorescent microscope.

Count the number of elementary bodies you see through the microscope (recall that elementary bodies stain green), enter the number of elementary bodies in the field below, and then click Submit to display your results in the grid. After you click Submit , the slide will automatically be placed in the biohazardous waste disposal. You answered: 0 elementary bodies

Experiment Data:

Sample Number of Elementary Bodies Chlamydia Result Patient A 0 Negative Patient B 17 Positive

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Post-lab Quiz Results You scored 80% by answering 4 out of 5 questions correctly.

1. In the serology test just performed, the fluorescence is found on the You correctly answered: c. antibody
2. What would most likely happen if you forgot to fix the samples to the slide? You correctly answered: a. They would all test negative because the washing steps would remove the samples.
3. Which sample showed some residual nonspecific binding after the washing steps? You correctly answered: c. patient C
4. Which patient samples contained the Chlamydia -specific antigen? You correctly answered: b. patient B
5. How is chlamydia disease transmission prevented? You did not answer this question.

Correct answer: d. abstinence or faithful, mutual monogamy

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Review Sheet Results

1. Describe the importance of the washing steps in the direct antibody fluorescence test. Your answer: La importania de realizar correctamente los lavados se debe a que consigue elminar las uniones no específicas, que nos darían un posible falso positivo
2. Explain where the epitope (antigenic determinant) is located. Your answer: Un anticuerpo tiene un lugar de unión con el antígeno. Está localizado en la supeficie de los glóbulos rojos.
3. Describe how a positive result is detected in this serological test. Your answer: Mediante la reacción de los cuerpos elementales (que se adhieren a las células huéspedes). Los cuerpos elementales toman un color verde y las células huésped un color verde.
4. How would the results be affected if a negative control gave a positive result? Your answer: No serviría. Es un falso positivo, habría que repetirlo todo.

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Experiment Results Stop & Think Questions: What must occur in order for an HIV-infected individual to test positive with the indirect ELISA test? You correctly answered: b. seroconversion

What is the key substance found in the developing buffer? You correctly answered: c. enzyme linked to the secondary antibody

Experiment Data:

Sample Optical Density HIV Test Result Positive Control 1.624 Positive Negative Control 0.154 Negative Patient A 0.054 Negative Patient B 0.432 Indeterminate Patient C 1.990 Positive

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Post-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly.

1. Antibodies are made of You correctly answered: a. protein
2. How would you describe the binding site of the secondary antibody? You correctly answered: c. the constant region of primary antibody
3. A positive result for HIV in the indirect ELISA performed contains You correctly answered: b. antibodies against HIV
4. Which patient needs to be retested? You correctly answered: b. patient B