Question

1. in what fraction of our blood (fluid or cellular) are the immunoglobulins (antibidies) such as igG or igM found ?

2. what is the usual source of the antigen for the latex agglutination test.

3. why is it that antigen-antibody complexes are visble in agggreated clumps, and yet red blood cells are microscopic?

4. streptococci are divided into diffrent groups called serotypes, what detrmines the diffrent serotypesb(A-O) of streptococci ?

Answer 1

Ans.

1. Immunoglobulin (igG and igM) are glycoprotein molecule produced by plasma cell( white blood cell) ,igG and igM predominate in plasma ,whereas igG and monomeric igA are the major isotype in extracellular fluid within the body .

IgM found mainly in the blood and lymph fluid ,is the first antibody to be made by the body to fight a new infection.

2. The latex agglutination test is a clinical method to detect certain antigens or antibodies in avariety of body fluid such as blood, saliva ,urine,or cerebrospinal fluid . The sample to be tested is sent to lab and where it mixed with latex beads coated with a specific antigen or antibody.

3. Antigen- antibody complex are visible in aggregated clump because agglutination reaction involve particulate antigens capable of binding antibody molecules . Since antibody molecule are multivalent ,suspended particulate antigens form large clumps or aggregates ,easily visible without magnification ,when exposed to specify antibody. The clumping of cells such as bacteria or RBC in the presence of antibody or other molecule binds multiple particles and join them ,creating a large clump.

Yet RBC is microscopic , approximately 7.8 micrometre in diameter and have to form biconcave disc .

4. Group B streptococci are common in the normal vaginal flora and ocassionally cause invasive neonatal infection . Group B streptococci typically show hippurate hydrolysis

Group beta- hemolytic streptococci are spread by respiratory secretion and fomites and also skin infection s peaks in childhood

Prompt penicillin treatment of streptococcal pharyngitis reduces the antigenic stimulus and prevents glomerulonephritis and rheumatic fever