Adaptive Immune Responses – Lecture Summary

Vocabulary flashcards summarizing key terms and processes of humoral and cell-mediated immune responses from the lecture notes.

Humoral Response (antibody-mediated)

Adaptive immune pathway that targets extracellular pathogens (e.g., bacteria) using antibodies produced by B cells.

Antigen-Presenting Cell (APC)

Cell such as a macrophage that ingests a pathogen and displays its antigen fragment on MHC II molecules.

MHC II

Major Histocompatibility Complex class II proteins that present extracellular antigen fragments to helper T cells.

Helper T Cell (Th)

T lymphocyte that recognizes antigen on MHC II and releases cytokines to activate B cells and other immune cells.

Cytokines

Signaling proteins released by immune cells (e.g., Th cells) to stimulate and regulate immune responses.

B Cell

Lymphocyte activated by Th-cell cytokines that differentiates into antibody-secreting plasma cells and memory B cells.

Plasma Cell

Effector B cell that produces and secretes large quantities of antibodies against a specific antigen.

Memory B Cell

Long-lived B cell that persists after infection, enabling a faster, stronger antibody response upon re-exposure.

Cell-Mediated Response

Adaptive immune pathway that targets intracellular pathogens (e.g., viruses, cancer) using cytotoxic T cells.

MHC I

Major Histocompatibility Complex class I proteins present on all nucleated cells that display intracellular antigen fragments to cytotoxic T cells.

Cytotoxic T Cell (Tc)

T lymphocyte that recognizes antigen on MHC I and kills infected or abnormal cells after activation.

Killer (Effector) Tc Cell

Activated cytotoxic T cell that releases perforin and granzymes to induce apoptosis in target cells.

Perforin

Protein released by killer Tc cells that forms pores in the membrane of the target cell.

Granzymes

Proteases delivered through perforin-formed pores that trigger apoptosis inside the target cell.

Apoptosis

Programmed cell death induced by immune mechanisms to eliminate infected or cancerous cells.

Memory Tc Cell

Long-lived cytotoxic T cell that provides rapid, enhanced cell-mediated immunity upon future infection with the same pathogen.