Question

Where are naïve T-cells converted to effector (able to respond to B-cell presentation) T-cells?

Bone marrow

Thymus

Lymphatic system

all of the above

Which of the following statements is not true of attenuated vaccines?

They have the potential to cause disease

They can spread to others

They induce a long-lasting immunity.

They do not require refrigeration

Which of the following is an example of a natural passive immunity?

natural exposure to infectious agent

mothers antibodies in breast milk

immunization with an attenuated vaccine

being administered an antitoxin

Which of the following statements is not true of B-cells?

they recognize MHC molecules.

they differentiate into plasma cells.

they present antigens to T-cells.

they bind to extracellular antigens.

Which of the following is an antigen presenting cell?

antibody producing lymphocyte

differentiated monocytes

cells with MHC class II molecules

all of the above

This cell type destroys cells bound by antibodies using apoptosis?

Cytotoxic T-cell

neutrophil

macrophage

Natural Killer Cell

Which of the following is not true of T-helper cells?

recognizes virus-infected cells

must be presented with an antigen

are activated by dendritic cells

produce cytokines

An exposure to which of the following might result in a Delayed cell-mediated hypersensitivity?

pollen

Rh negative blood

pet dandruff

Mycobacterium tuberculosis

The use of the TB test to monitor for tuberculosis exposure takes advantage of this type of hypersensitivity?

Immediate IgE mediated

Cytotoxic

Immune-complex

Delayed cell mediated

Answer 1

Ans.1:

Naive T Cells are those cells been differentiated in bone marrow. A naive T Cells can only travel through lymph nodes and the spleen. They are inaccessible to non lymphomatic areas in the body. Eventhough the effector Cells can access the non lymphomatic areas of the body, they must first reach the lymphoid organs inorder to convert the naive T Cells into effector T cells.

Hence, the answer is 'Lymphatic system'.

Ans.2:

Attenuated vaccines are those which are created out of a pathogen, by reducing its virulence effect, but are still live and viable to infections due to secondary mutation, which can cause reverse virulence,but in very rare cases though.That is, it can attack back causing severe infection sometimes that can be further transferred to others. While most of the attenuated vaccines tolerates extreme low temperatures, they tend to loose their function by rapid change in temperature if removed from refrigerated storage. Attenuated vaccines like, Influenza (LAIV),rotavirus(RVI) etc must be kept referigerated.

Hence, the answer is 'They do not require refrigeration'., which is false.

Ans.3:

Natural Passive Immunity refers to those passive immunities that occurs naturally, such as transfer of antibodies into an infant through breast feeding, as the mothers milk contains antibodies.During pregnancy,while inside the womb, a fetus recieves natural passive immunity through the placenta.Other passive immunities that are received though injections are artificial passive immunities.

Hence, the answer is ' mothers antibodies in breast milk'.

Ans.4:

B Cells are a part of an adaptive immune system that functions as an antibody secreting agent in the humoral immunity component. They can bind to antigens due to the presence of B Cell receptors, and differentiate ino plasma cells,thereby releasing antibodies to prevent from harmful infections.

Hence, the answer is ' they recognize MHC molecules',as it is false. MHC molecules are recognized by appropriate T Cells, not B Cells.