Question

Which of the following cells of connective tissue secrete antibodies?
a. Mast cells
b. Reticular cells
c. Adipose cells
d. Plasma cells

Answer 1

Hint: Antibodies are the glycoproteins which help the body in fighting against infections. They have receptors corresponding to antigenic epitopes and thus antigen- antibody reaction is specific. They are produced and found on the cells of the immune system called B cells.

Complete answer:
> Mast cells- These cells are migrant cells of connective tissue having histamine and heparin rich granules. They are basically involved in allergic reactions and are derived from myeloid progenitor cells in the bone marrow.

> Reticular cells- These cells are a type of fibroblast synthesizing collagen alpha- 1(III), which is used for producing reticular fibers surrounded by cytoplasm of the cells, thus isolating it from other tissue cells and components. They serve to provide structural support by providing and maintaining a thin network of fibers which form the framework for most of the lymphoid organs.

> Adipose cells- These are the cells derived from mesenchymal stem cells through the process of adipogenesis. They are also known as fat cells and are primarily associated with fat storage.

> Plasma cells- These are the cells which have been developed from B- lymphocytes. When naive B lymphocytes encounter antigen, they differentiate into effector cells and memory cells. The effector cells are called plasma cells and they secrete antibodies which are specific to the antigenic epitope that was encountered.

Hence, the correct answer is option (D).

Note: All the antibodies produced from a single clone of B cells have the same specificity.
- There are 5 isotypes of antibodies- IgE, IgD, IgA, IgG, and IgM.
- T- lymphocytes are other significant cells of the immune system which play a role in both humoral and cell-mediated immunity.
- Plasma cells contain many Endoplasmic Reticulum to support the high rate of protein synthesis. They also have many Golgi vesicles.