Question

The standard HIV test detects HIV antibodies rather than the virus itself. When a person becomes infected with HIV, it takes a few weeks for the HIV test to indicate a positive result. Based on the information provided, which of the following processes occurs in the time between infection and detection?

A) cell-mediated immunity

B) more macrophages are produced

C) more viruses are produced

D) humoral immunity

Answer 1

Answer is option A

Cell mediated immunity

HIV invades various immune cells (e.g., CD4+ , T cells and monocytes) resulting in a decline in CD4+ T cell numbers below the critical level, and loss of cell-mediated immunity . It then thus produces secondary infections.

By infecting CD4+ T cells, HIV is able to replicate predominantly in activated T cells and paralyse one of the main components of adaptive immune system. HIV can also establish latent infection in CD4+ T cells and remain invisible to CD8+ T cells and therefore replication can occur later in the infection and generate new virions. Antigenic mutation within the T-cell epitopes can affect the binding capacity of MHC molecules to the viral peptides, resulting in the inability of the TCRs to recognise the MHC-peptide complex. Finally, HIV is able to hide from anti-HIV antibodies by expressing non-immunogenic glycans on key antibody epitopes.