​An anti-idiotypic antibody with fluorescent tag was used for detection of immune cells in tissue sections from a healthy individual specifically by cell surface labeling. Which of the following will have the highest chances of getting detected?​

Correct option is B

Explanation-

Option B – Mature B cells in spleen
Anti-idiotypic antibodies recognize the antigen-binding site (idiotype) of surface immunoglobulins (Igs) on B cells. Mature B cells in the spleen express membrane-bound immunoglobulins (IgM and IgD) as B-cell receptors (BCRs). These surface immunoglobulins are ideal targets for anti-idiotypic antibodies. The spleen is a primary lymphoid organ rich in mature, naive and memory B cells. These B cells actively express surface immunoglobulins, which can be detected using anti-idiotypic antibodies. These cells are not yet terminally differentiated, so they retain high levels of surface Ig, unlike plasma cells which reduce surface Ig expression.

Incorrect options -
Option A -  Macrophages in lymph nodes
Do not express immunoglobulins and not involved in antibody recognition via idiotypes.
Option C -  Terminally differentiated plasma cells in lymph nodes
Plasma cells secrete antibodies, but they downregulate surface Ig. Hence, less suitable for detection by surface-labeling anti-idiotypic antibodies.
Option D -  Eosinophils in tonsils
Eosinophils are granulocytes, unrelated to antibody production. They do not express surface Igs.


So, Option B (Mature B cells in spleen) is correct