Which of the following is an example of low immunogenicity?

• A. Johne's disease (MAP)
• B. Rabies
• C. Parvovirus
• D. Panleukopenia

Answer: (A)

Immunogenicity is the ability of an antigen to provoke an immune response. Johne’s disease agent, Mycobacterium avium subspecies paratuberculosis (MAP), tends to provoke only a weak and delayed immune response. It grows slowly and survives inside macrophages, and its cell wall components blunt immune recognition, leading to a long subclinical period with scant antibody production. This makes MAP a classic example of low immunogenicity, as the host’s immune system doesn’t mount a strong or early antibody or cellular response.

In contrast, rabies virus, parvovirus, and panleukopenia virus typically induce robust immune responses, with clear antibody production or strong cell-mediated activity following infection or vaccination, highlighting higher immunogenicity.