Which of the following best describes the difference in the...

Which of the following best describes the difference in the way B cells and cytotoxic T cells deal with invaders? a. $\mathrm{B}$ cells confer active immunity; T cells confer passive immunity. b. $\mathrm{B}$ cells send out antibodies to attack; certain T cells can do the attacking themselves. c. $\mathrm{T}$ cells handle the primary immune response; B cells handle the secondary response. d. $\mathrm{B}$ cells are responsible for the cell-mediated immune response; T cells are responsible for the humoral immune response.

Which of the following best describes the difference in the way B cells and cytotoxic T cells deal with invaders?
a. $\mathrm{B}$ cells confer active immunity; T cells confer passive immunity.
b. $\mathrm{B}$ cells send out antibodies to attack; certain T cells can do the attacking themselves.
c. $\mathrm{T}$ cells handle the primary immune response; B cells handle the secondary response.
d. $\mathrm{B}$ cells are responsible for the cell-mediated immune response; T cells are responsible for the humoral immune response.

Key Concepts

Cell-Mediated Immunity

Cell-mediated immunity is the branch of the immune system that does not involve antibodies but rather relies on the activation of T cells, including cytotoxic T cells, to directly eliminate infected cells. This response is crucial for handling intracellular pathogens and abnormal cells.

Humoral Immunity

Humoral immunity involves the production of antibodies by B cells to target pathogens circulating in body fluids. The antibodies bind to antigens on pathogens, facilitating their removal through various mechanisms such as neutralization and opsonization.

B Cells

B cells are a type of lymphocyte that primarily function in the humoral immune response by producing antibodies, which recognize and bind to specific antigens on pathogens. This antibody production helps neutralize invaders and mark them for destruction by other components of the immune system.

Cytotoxic T Cells

Cytotoxic T cells are specialized lymphocytes that play a key role in the cell-mediated immune response. They directly attack and destroy infected or cancerous cells by recognizing antigens presented on the surface of these cells in association with MHC class I molecules.

Transcript

00:01 This question asks us to choose the answer option that best describes the difference in the way that b cells and cytotoxic t cells deal with invaders.

00:14 So just for a quick review about b cells and t cells, b cells are responsible for the humoral immune response, which defends primarily against bacteria and viruses present in bodily fluids.

00:31 Okay, so with that in mind, we're already looking at option d with great suspicion.

00:39 We know that this answer is false because it is saying the opposite that b cells are responsible for cell -mediated immune response, and we know that that is not true.

00:50 We'll get to it in a second, but they basically just have the role for b cells and t cells reversed.

00:55 So already one answer gone.

00:59 Okay.

01:00 Carrying on, in response, b cells secrete antibodies into the blood and lymph.

01:09 Antibodies mark invaders by binding to them and the resulting antigen antibody complexes are easily recognized for destruction and disposal by phagocytosis of a couple different kinds of cells.

01:23 Okay, t cells are responsible for the cell -mediated immune response.

01:29 Okay, so we've definitely double -checked.

01:32 This answer d is for sure wrong.

01:36 Just as a reminder, the cell -mediated immune response defends against infections inside body cells.

01:45 A type of t -cell called a helper t -cell triggers both the humoral and cell -mediated immune responses.

01:53 Helper t -cells themselves do not carry out these responses, and instead, signals from helper t -cells, initiate the production of antibodies in b cells that neutralize pathogens, and also these helper t cells, activate the cytotoxic t cells that will kill infected body cells.

02:15 Okay, so let's work through the rest of these answer choices and see what we have.

02:25 So for option a, recall that active immunity and passive immunity are all about antibody production.

02:35 In active immunity, you produce your own antibodies, and in passive immunity, you acquire pre -made antibodies...

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