Which of the following statements concerning cellular immunity is false?
The thymus is necessary for development of cells involved in cellular immunity.
Cell-mediated immunity (a.k.a. cellular immunity) is the targeting and destruction of intracellular pathogens by T cells.
Cellular immunity involves cells that recognize antigens and make specific antibodies against them.
The lymphocytes involved with cellular immunity are found primarily in lymphoid organs and blood.
T cells respond to antigens when the antigens bind to receptors on their surface.
The correct answer and explanation is :
Correct Answer:
“Cellular immunity involves cells that recognize antigens and make specific antibodies against them.”
Explanation:
Cellular immunity, also known as cell-mediated immunity, is primarily carried out by T cells rather than B cells. Unlike humoral immunity, which relies on antibodies produced by B cells, cellular immunity involves direct interactions between T cells and infected or abnormal cells.
Here’s why the statement is false:
- T Cells Do Not Produce Antibodies
- Antibodies are exclusively produced by B cells, particularly plasma cells, in response to antigen exposure.
- T cells, on the other hand, function by recognizing infected or abnormal cells and initiating immune responses through cytokine release or direct cytotoxic action.
- How Cellular Immunity Works
- T cells identify infected cells, cancerous cells, or foreign substances by recognizing antigen-presenting cells (APCs) that display foreign antigens using major histocompatibility complex (MHC) molecules.
- Helper T cells (CD4+) coordinate immune responses by releasing cytokines that activate other immune cells.
- Cytotoxic T cells (CD8+) directly kill infected or cancerous cells by inducing apoptosis (cell death).
- Clarifying the Other Statements
- The thymus is essential for T cell development, which is true.
- T cells respond to antigens binding to their surface receptors, which is also correct.
- Lymphocytes, including T cells, are found in lymphoid organs and blood, reinforcing their role in immune surveillance.
Thus, the false statement is the one suggesting that cellular immunity involves antibody production, since T cells do not produce antibodies—only B cells do.
Here is an image illustrating the differences between cellular immunity (T cells) and humoral immunity (B cells):
