Sangstat Medical Corporation

Equal Access To Scientific Excellence

Peter Chun

Philippe J Pouletty

Kai Ling Yao

Chin H Chang

A sequential solid phase immunoassay and system is disclosed. The immunoassay utilizes the secondary antibody method for the detection of antibodies in a membrane-based test. The system comprises a test strip including a nitrocellulose membrane having an immobilized antigen in a capture zone on the membrane and a stabilized liquid secondary antibody conjugate. The sequential solid phase immunoassay is performed in a sequential manner with the addition of a fluid specimen being followed by the addition of the stabilized liquid secondary antibody conjugate. The sequential procedure using the system includes allowing the fluid specimen containing antibodies specific to the antigen to pass laterally from the test strip first end through the capture zone. The immobilized antigens in the capture zone capture antibodies specific to the antigen. The stabilized liquid secondary antibody conjugate then binds to the captured antibodies and can be detected visually or by a machine or reader.

Sequential solid phase immunoassay including contact pad to limit conjugate flow during manufacture

Methods and compositions are provided for detecting HLA polymorphs where distinguishing antibodies are not readily available. Cross-reactive antibodies are employed, where one cross-reacts with the HLA of interest and other alleles, and the other cross-reacts with one of the other alleles, but not with the HLA of interest. By appropriate protocols and controls, the polymorph of interest may be detected.

HLA typing

Physiological samples are typed for HLA-B27 by contacting the sample with an antibody which binds to HLA-B7 and is not cross-reactive between HLA-B7 and B27, separating the sample from any complexes which are formed, and then testing the sample for the presence of HLA-B27 with an antibody which is cross-reactive for HLA-B7 and B27 in a STAT test. Particularly, an enzyme conjugate is used which binds to a membrane allowing for the detection of any HLA-B27 bound to the membrane.

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South San Francisco, CA, United States of America

Peter Chun