Patent ID: 7247439

Claim:
In a patient infected with a virus, a method for detecting an antibody response capable of blocking virus infection comprising: a) transfecting into a first sample of cells i. nucleic acids encoding envelope proteins of a population of virus infecting the patient, and ii. a viral expression vector which lacks a nucleic acid encoding an envelope protein, and which comprises an indicator nucleic acid which produces a detectable signal, such that the first sample of cells produces viral particles comprising envelope proteins from the population of virus infecting the patient, b) contacting the viral particles of step (a) with an antibody preparation from the patient; c) contacting the viral particles and antibody preparation of step (b) with a second sample of cells, wherein the second sample of cells express a cell surface receptor and/or co-receptor which binds to the virus; d) measuring the amount of detectable signal produced by the second sample of cells in step (c) in order to determine the infectivity of the viral particles; and e) contacting the viral particles of step (a) with a second sample of cells, wherein the second sample of cells express a cell surface receptor and/or co-receptor which binds to the virus; f) measuring the amount of detectable signal produced by the second sample of cells in step (e) in order to determine the infectivity of the viral particles; and g) comparing the amount of signal measured in step (d) with the amount of signal produced in step (f), wherein a decrease in the amount of signal with the antibody treated viral particles indicates that the patient has developed an antibody response capable of blocking virus infection.