Mucosal Immunity

Question 1

Mucosal immunity:

Answer 1

The immune response that protects the mucosal surfaces (e.g., gut, respiratory tract, urogenital tract) from pathogens while maintaining tolerance to non-harmful antigens.

Question 2

Mucosal-associated lymphoid tissues (MALT):

Answer 2

Lymphoid tissues found at mucosal surfaces, including the tonsils, Peyer’s patches, and other lymphoid follicles.

Question 3

Peyer’s patches:

Answer 3

Specialized areas of MALT in the small intestine that sample antigens and initiate immune responses.

Question 4

Mucosal surfaces:

Answer 4

Sites exposed to the external environment, including the respiratory, gastrointestinal, and urogenital tracts, where pathogens are commonly encountered.

Question 5

IgA antibodies:

Answer 5

The main antibody isotype produced at mucosal sites, secreted into the mucus to neutralize pathogens and prevent them from entering the body.

Question 6

Secretory IgA (sIgA):

Answer 6

A dimeric form of IgA found in mucosal secretions that provides immune protection at mucosal surfaces.

Question 7

Dendritic cells in mucosal immunity:

Answer 7

Capture and process antigens at mucosal surfaces, then migrate to lymph nodes to activate T and B cells.

Question 8

M cells:

Answer 8

Specialized epithelial cells in MALT that transport antigens from the lumen to underlying immune cells, initiating immune responses.

Question 9

T-cell responses in mucosal immunity:

Answer 9

T cells in mucosal tissues (e.g., Th17, Treg cells) regulate the immune response and maintain tolerance to harmless antigens.

Question 10

Th17 cells in mucosal immunity:

Answer 10

Helper T cells that promote inflammation and defense against extracellular pathogens, especially at mucosal surfaces.

Question 11

Regulatory T cells (Tregs) in mucosal immunity:

Answer 11

Help maintain immune tolerance at mucosal surfaces, preventing inappropriate immune responses to harmless antigens.

Question 12

Mucosal tolerance:

Answer 12

The immune system’s ability to ignore non-pathogenic antigens at mucosal sites, such as food proteins and commensal bacteria.

Question 13

Oral tolerance:

Answer 13

Immune tolerance induced through oral exposure to antigens, preventing immune responses to food and gut microbiota.

Question 14

Gut-associated lymphoid tissue (GALT):

Answer 14

A type of MALT located in the gastrointestinal tract, involved in sampling antigens and initiating immune responses.

Question 15

Lung-associated lymphoid tissue (LALT):

Answer 15

A type of MALT found in the respiratory tract, where immune responses to inhaled pathogens are initiated.

Question 16

Mucosal vaccination:

Answer 16

Vaccines designed to stimulate mucosal immunity, often using oral or nasal routes, to provide protection against infections at mucosal surfaces.

Question 17

Commensal microbiota and mucosal immunity:

Answer 17

The normal flora in mucosal tissues that help protect against pathogens by competing for resources and stimulating immune responses.

Question 18

Antigen sampling by MALT:

Answer 18

Antigens from the external environment are captured by cells in MALT (e.g., M cells, dendritic cells) and presented to immune cells to initiate an immune response.

Question 19

Intraepithelial lymphocytes (IELs):

Answer 19

T cells located in the epithelial layer of mucosal tissues that play a role in immune defense and tissue homeostasis.

Question 20

Mucosal immune responses to pathogens:

Answer 20

Rapid and efficient immune responses at mucosal surfaces involving IgA production, T cell activation, and inflammatory responses.

Question 21

Mucosal immunization and memory:

Answer 21

Immunization via mucosal routes generates long-lasting immunity at mucosal sites, providing protection upon re-exposure to pathogens.

Question 22

Mucosal inflammation:

Answer 22

Inflammatory responses at mucosal surfaces caused by infection or injury, leading to symptoms like swelling, redness, and pain.

Question 23

Toll-like receptors (TLRs) in mucosal immunity:

Answer 23

Pattern recognition receptors on mucosal immune cells that recognize microbial patterns and trigger immune responses.

Question 24

Mucosal immune defense mechanisms:

Answer 24

Include physical barriers (mucus, epithelial cells), innate immunity (complement, antimicrobial peptides), and adaptive immunity (IgA, T cells).

Question 25

Epithelial cell function in mucosal immunity:

Answer 25

Epithelial cells act as a physical barrier and secrete antimicrobial peptides and cytokines to defend against pathogens.

Question 26

Mucosal vaccines (e.g., oral polio vaccine):

Answer 26

Designed to stimulate IgA production at mucosal surfaces to prevent pathogen entry and infection at these sites.

Question 27

Induction of mucosal immune responses:

Answer 27

Involves antigen uptake by specialized cells (e.g., dendritic cells, M cells) and the activation of local T and B cells at mucosal tissues.

Question 28

Immune exclusion:

Answer 28

The process by which IgA antibodies prevent pathogens from adhering to and invading epithelial cells at mucosal surfaces.

Question 29

Mucosal immunity and allergy:

Answer 29

Defects in mucosal immune regulation can contribute to allergic diseases, such as allergic rhinitis or asthma, where inappropriate immune responses are triggered.