T Helper Cells and Immune Response

These flashcards cover key concepts related to T helper cells, immune response, antigen presentation, and the role of CD4 and CD8 T cell types in the adaptive immune system.

What are CD4 cells commonly known as?

T helper cells.

What is the role of antigen presenting cells in the immune response?

They present antigens to T cells, allowing T cells to respond to these antigens.

How do T helper cells recognize antigens?

Via T cell receptor that binds to antigens presented on MHC II.

What are the two main steps required for T cell activation?

Antigen binding and costimulation.

What chemical does the antigen presenting cell release to stimulate T helper cells?

Interleukin 1 (IL-1).

What is the significance of IL-2 in T cell activation?

It co-stimulates T helper cells and activates other immune cells.

In which part of the body do T cells mature?

In the thymus.

What is a key characteristic of cytotoxic T cells (CD8 cells)?

They bind to antigens presented on MHC I and can kill infected or cancerous cells.

What is the effect of HIV on the immune system?

HIV attacks and destroys CD4 T helper cells, impairing the immune response.

What occurs if there are no functional CD4 T cells in the immune system?

Without CD4 T cells, there is no effective immune response; B cells and CD8 T cells cannot be properly activated.

What is the difference between HIV and AIDS?

HIV is the virus that causes the infection, while AIDS is the syndrome that develops when an HIV-infected person's immune system is severely compromised.

What happens during the process of costimulation for T cells?

After initial antigen binding, a second signal from co-stimulatory molecules or cytokines is required for full T cell activation.

How do T cell effectors differ from B cell effectors?

T cell effectors do not have a unique name like plasma cells for B cells; they are generally referred to as T cell effectors.

What is the role of perforin and granzymes produced by cytotoxic T cells?

Perforin forms pores in target cell membranes, while granzymes enter through these pores to induce apoptosis.

Why is there a focus on both exogenous and endogenous antigens in T cell activation?

To ensure T cells can respond to a range of pathogens, both those that originate outside cells (exogenous) and those that arise from within cells (endogenous, like cancerous or viral proteins).

What is the main difference in antigen recognition between CD4 and CD8 T cells?

CD4 T cells recognize exogenous antigens on MHC II, while CD8 T cells recognize endogenous antigens on MHC I.

What is a T cell's 'T cell receptor' (TCR) responsible for?

The TCR is specifically designed to recognize and bind to specific antigens presented by MHC molecules.