In global health programmes, the Enzyme-Linked Immunosorbent Assay (ELISA) is a critical diagnostic tool used to monitor the prevalence of HIV by screening blood samples. In an indirect ELISA test designed to detect anti-HIV antibodies in patient serum, a false-positive result can occur if the procedure is not performed precisely.
Which of the following describes the most likely cause of a false-positive result in this monitoring test?
Insufficient washing of the wells after the addition of the enzyme-linked secondary antibody, leaving unbound conjugate that reacts with the substrate.
A high concentration of active helper TTT-lymphocytes in the patient's serum, which directly bind to the enzyme and trigger a non-specific color change.
Over-washing with a high-salt buffer, which causes the immobilized HIV antigens to denature and bind directly to the color-changing substrate.
Rapid somatic mutation of the patient's primary antibodies during the 37∘C37^\circ\text{C}37∘C incubation phase, converting them into active enzymes.