Improved ELISA to measure thymosin alpha 1: comparison of whole and absorbed antisera.
An improved microELISA to measure thymosin alpha 1 (T alpha 1) is described which uses a rabbit antibody against T alpha 1 that has been absorbed with a synthetic C-14 fragment of T alpha 1. This assay is compared to the previous assay which used the whole antisera. The antibodies to T alpha 1 are preincubated with the standard or human sera overnight at 4 degrees C, then incubated for an additional 24 h in microtiter plates coated with T alpha 1. Using the whole antiserum, the average T alpha 1 level was 2480 +/- 1110 (mean +/- S.D.) pg/ml by ELISA and 2360 +/- 870 pg/ml by radioimmunoassay (RIA) in eight different samples of human cord sera. Using the N-specific absorbed antiserum the mean T alpha 1 level was 11,800 +/- 4800 pg/ml by ELISA and 10,600 +/- 5200 pg/ml by RIA. Recoveries of exogenously added T alpha 1 are complete (109 +/- 25% for whole and 108 +/- 15% for absorbed antisera). The absorbed antiserum has an increased affinity for the amino acid terminal region of T alpha 1 and the T alpha 1 values by use of absorbed antisera are significantly higher (3-5 x) than those measured using the whole antisera. Thus, the absorbed antisera produces an ELISA which is more sensitive and specific for serum thymosin alpha 1.
Wada
S
S
Department of Biochemistry, George Washington University School of Medicine and Health Sciences, Washington, DC 20037.
Naylor
P H
PH
Naylor
C W
CW
Goldstein
A L
AL
D000906:Antibodies; D004797:Enzyme-Linked Immunosorbent Assay; D005312:Fetal Blood / Q000032:analysis; D006801:Humans; D007231:Infant, Newborn; D011863:Radioimmunoassay; D012015:Reference Standards; D000077596:Thymalfasin; D013947:Thymosin / Q000031:analogs & derivatives* / Q000097:blood / Q000276:immunology / Q000592:standards
D000906:Antibodies; D013947:Thymosin; D000077596:Thymalfasin