Designing of HIV P24 Antigen assay kit using human monoclonal Antibody

Subject Areas : Diagnostic Microbiology

Masoomeh Hashemi ¹ , Seyed-Mehdi Butorabi ² , Reza Haji-Hoeini ³ , Ali Mir-Jalili ⁴

1 - Department of Biochemistry, Payam-noor University, Tehran Branch, Tehran, Iran
2 - Pishtaz-Teb Company, Tehran, Iran
3 - Department of Biochemistry, Payam-noor University, Tehran Branch, Tehran, Iran
4 - Department of Biotechnology, Razi vaccine and serum research institute, Tehran branch, Tehran, Iran

Received: 2009-06-15 Accepted : 2009-07-16 Published : 2009-07-01

Keywords: HIV, ELISA Test, antigen P24, Immunity Measurement,

Abstract :

Background and Objective: Several days after infection with HIV and before serum changes in the stage that there is RNA HIV in the blood, the antigen P24 of the HIV is measurable in the blood. The studies done show that in the primary stages of the infection, antigen p24 appears sooner than antibody; therefore, the evaluation of antigen p24 can be an appropriate index for diagnosing the infection in the first stages of the disease. Materials and Methods: 300 negative samples from blood donor were tested with the third-generation kit for determining the antibody against HIV. 30 positive samples were collected from the AIDS Research Center and the patients confirmed with Immunoblot and NAT methods. All the samples were investigated with the designed kit for antigen p24 in Elisa method. From among the samples, the samples of serums the antibody test of which were positive, pretreatment with different solutions including 1.5 molars of Buffer Glycin with PH=2, hydrochloric acid 0.5 N, Trition X-100 with a concentration of 0.1% , alkaline buffer No.1 and 2 for removing the probable interventional effect of antibody against antigen p24. Result: From among 30 positive samples, 21samples of antigen tests were positive in the kit designed by human monoclonal and 18 cases in the kit designed by mouse monoclonal antibody before pretreatment samples with Glycin (the diagnostic sensitivity is 70% and 60% respectively). After pretreatment, 28 samples in the kit designed by human monoclonal antibody and 27 samples in the kit designed by mouse monoclonal were positive.( the diagnostic sensitivity were 93% and 90% respectively). In the kit designed for detecting antigen p24, the cut off was determined on the basis of optical density of the negative samples 0.15(equal to 2 pg/ml of antigen P24). The difference between the average of optical density of the positive and negative samples in antigen test was significant statistically(pConclusion: This test has high sensitivity and specificity in diagnosing HIV and is more simple, fast, accurate, and economical in comparison with other diagnostic methods. This test may be used for screening newborns from the mothers with positive HIV and the taking decision about the cases for whom the fourth-generation of Elisa Tests are positive but Western Blot Test has not confirmed it.