University:
University of Cincinnati Blue Ash
Course:
BIOL 5180 | Immunology
Academic year:

2024
Views:

175

Pages:

1
Author:

Jasper J.

ASTO / ASO inspection Basic theory Beta hemolytic streptococcus secretes an enzyme called O streptolysin which is capable of lysing red blood cells. O streptolysin acts as an antigen and stimulates the immune system to form O antistreptolysin (ASO) antibodies. High ASO titer levels indicate that streptococcus is present and can cause rheumatic fever/acute glomerulonephritis. Elevated serum ASO levels may also indicate recent streptococcal infection. ASO antibodies appear approximately 1 to 2 weeks after acute streptococcal infection, peak 3 to 4 weeks after the reaction, and remain elevated for months. Many school-aged children have higher ASO titer levels than pre-adult or adult children. Other streptococcal antigens are antideoxyribonuclease (ADNase – titer >10) and antistreptococcal hyaluronidase (ASH – titer >128). Purpose of inspection To determine antibodies against β-hemolytic Streptococcus which causes rheumatism, tonsillitis and glomerulus Principle Latex agglutination uses latex particles coated with streptolysin O, then reacting this with the patient's serum. The presence of anti-streptolysin in the patient's serum is expressed by the occurrence of agglutination and these particles. Tools and reagents Tool Reagent contains ASO antibodies; latex reagent = suspension of polysiterin latex particles coated with Streptolysin O Ways of working a) Reagents and serum are incubated at room temperature b) Drip 50 µl of patient serum into the slide hole. c) Shake the latex reagent, then drop it into the hole with the dropper provided. d) Mix the droplets using a stirrer to ensure all test holes are mixed. e) rotate the test slide, for 2 minutes see the agglutination that occurs. Interpretation of results a) Positive: When agglutination occurs b) Negative: If no agglutination occurs