Adaptive Immune System Mini-Review

Which is NOT a characteristic of adaptive immunity?

• carried out by lymphocytes

• has memory

• specific

• fast

Answer explanation

Compared to innate immunity, adaptive resonse is slow to a new antigen. After the 1st exposure, memory cells are left behind for a stronger response the next time the same antigen is encountered.

Which is true of humoral immunity?

• It involves B-lymphocytes.

• It involves antibody production.

• It involves cytotoxic T-cells.

• It kills infected host cells.

Answer explanation

From humoral immunity we get antibodies which specifically bind to antigens, neutralize them & target them for destruction.

Cell-mediated immunity is targeted against _______?

• bacteria

• extracellular viruses

• viral infected "self" cells

• cancerous cells

Answer explanation

Cytotoxic T-cells recognize viral and tumor antigens displayed on a host cell MHCI. Message is, "I am self, but have been infected. Kill me now."

When lymphocytes leave the thymus, they are called ________.

• effector T-cells

• naive T-lymphocytes

• memory T-cells

• B-cells

Answer explanation

T-cells are made in the bone marrow and go to the thymus gland to mature. When they leave, they haven't encountered their antigen yet, so they are called "naive".

Which lymphocyte gives the confirmation signal for activation for both humoral and cell mediated response to an antigen?

• B-cell

• APC antigen presenting cell

• CD8

  cytotoxic T-cell

• CD4

  Helper T-cell

Answer explanation

T-helper cells are the "Generals" of your immune system army. They make cytokines (chemical messengers) that activate B-cells, T-cells & macrophages.

Which of the following are APCs antigen presenting cells?

• T-cells

• macrophages

• dendritic cells

• B-cells

Answer explanation

T-cells only recognize a fragment of an antigen when diplayed in the context of a MHC - major histocompatibility complex.

Which type of cell secretes antibodies?

• B-cells

• plasma cells

• CD4

  T-helper cells

• APCs antigen presenting cells

• CD8

  cytotoxic T-cells

Answer explanation

B-cells BECOME plasma cells when activated. They are the effector cells of humoral immunity.

In which type of response is there a lag period?

• innate immune response

• primary immune response

• secondary immune response

• all immune responses

Answer explanation

The lag period in a primary response is the time it takes for the antigen to encounter the appropriate lymphocytes & for activation to occur. There are memory cells for the secondary response which react much FASTER & stronger.

The 1st class of antibody made in a primary response is?

• IgG

• IgA

• IgM

• IgE

Answer explanation

IgM in a primary response. Then there is class switching & plasma cells make IgG.

Which class of antibody is present in secretions such as mucus, tears & saliva?

• IgG

• IgA

• IgM

• IgE

Answer explanation

Secretory IgA is in secretions that bathe & protect mucosal surfaces. IgA is also secreted in colostrum and breast milk.