Antibody- and cell-mediated effector mechanisms week 10

How do cytotoxic T cells (CTLs) differ from natural killer (NK) cells in targeting infected cells?

A. CTLs do not kill infected cells

B. CTLs require antigen presentation, NK cells do not

C. NK cells use antibodies, CTLs do not

D. CTLs only respond to bacteria

CTLs require antigen presentation, NK cells do not

In ADCC, NK cells recognise antibody-coated target cells through ________, allowing them to release cytotoxic granules.

Fc receptors

What triggers NK cells to kill a target cell?

The absence of MHC class I and the presence of stress proteins on the cell surface.

What is the role of opsonins in the immune response?
A. They digest pathogens inside phagocytes
B. They neutralize toxins
C. They coat pathogens to enhance phagocytosis
D. They produce antibodies

They coat pathogens to enhance phagocytosis

Which immune cells are primarily responsible for Antibody-Dependent Cellular Cytotoxicity (ADCC)?
A. B cells
B. Neutrophils
C. Natural killer (NK) cells
D. Cytotoxic T cells

Natural killer (NK) cells

How do antibodies neutralize bacterial toxins?
A. By converting them into harmless molecules
B. By preventing their interaction with host cells
C. By signaling other cells to destroy them
D. By digesting them directly

By preventing their interaction with host cells

Which type of antibody is most effective at agglutination due to its high number of binding sites?
A. IgA
B. IgE
C. IgG
D. IgM

IgM

What is the main function of memory T cells?
A. Immediate killing of pathogens
B. Production of antibodies
C. Remembering pathogens for faster future responses
D. Activating B cells

Remembering pathogens for faster future responses

How do NK cells avoid killing healthy cells?
A. They detect antibodies
B. They are activated only during infections
C. Healthy cells express MHC class I molecules that inhibit NK activity
D. Healthy cells produce anti-stress proteins

Healthy cells express MHC class I molecules that inhibit NK activity.

Opsonization helps phagocytes recognize pathogens by tagging them with ____

opsonins

In ADCC, NK cells release ____ and ____ to induce apoptosis in target cells.

perforin granzymes

Antibodies neutralize viruses by preventing their ______ to host cells.

attachment

__antibodies are particularly effective in agglutination due to having ten binding sites.

IgM

NK cells target cells that lack ___ ____ _ molecules and express

MHC class I stress proteins

What does opsonization do in the immune system?

It marks pathogens with opsonins to enhance their uptake by phagocytes.

What happens during ADCC?

NK cells recognize antibody-coated cells and kill them using cytotoxic molecules.

How do antibodies neutralize bacterial exotoxins?

By binding to them and preventing interaction with host cells.

What makes IgM effective at agglutination?

It has 10 antigen-binding sites, allowing it to clump pathogens efficiently.

What is the function of cytotoxic T cells versus memory T cells?

1. Cytotoxic T cells kill infected cells; memory T cells provide long-term immunity.