Question

1.Name the exocrine glands that belong to mucosal immune system.

2. Give the definition of commensal bacterium.

3. In this list, which belongs to peptide’s group?

a. Histatin b.Phospholipase A c. Lysozyme L d. β-defensin

4. M cells produce the mucus in the gastrointestinal track

True or False

5 .B cells present the antigen to dendritic cells that secrete Igs

True or False

6. α-defensins are secreted by

a. M cells b. Macrophages c.paneth cells d.Intraepithelial cells

7. Name minimum 3 markers express on IELs.

8. In the blood, we find monomer of IgA

True or False

9. Salmonella typhimurium is a commensal bacterium.

True or False

10. Give 5 riks factors for inflammatory bowel disease.

Answer 1

1. Salivary gland, lachrymal gland, pancreas and mammary glands.

2.Commensalism is a type of interaction between two oraganism in which one of the organism is benefitted from the other organism without cuasing any harm or benefit to it. In case of bacteria also we can see commensalism. for example bacteria found on human skin, respiratory tract, gastrointestinal lining, etc are not doing us any harm. they get a place to live and also nutrients required to grow. they usually does not cause any harm. but sometimes they may turn into pathogens causing diseases.Eg. of such bacteria in humans are Corynebacterium species and mycoacterium species.

3. All proteins are made up of amino acids. amino acids are joined by peptide bonds. all enzymes are proteins. so all ezymes contain peptide bonds.

β defensins are antimicrobial peptides belonging to mammalian defensins which protect epithelial surface aginst microbial colonization.

Histatins are a family of histidine rich cationic peptides with antimicrobial properties secreted by salivary glands into human saliva. it mainly fights against infections caused by fungi Candida.

Phospholipase is an enzyme that can breakdown phospholipids. they are proteins and have peptide bonds. There are four major classes of phospholipase enzymes, they are Phospholipase A,B,C and D.

Lysozyme is an antimicribial enzyme produced by animals. it belongs to the innate( inborn) immune system.

4. Microfold cells or M cells do not secrete mucus or digestive enzymes. They are found in the gut associated lymphoid tissue and also in mucosa associated lymphoid tissues in the gastrointestinal lining. Thses cells are known to initiate mucosal immune response.

5. B cells, also called B lymphocytes are a type of white blood cells (WBC). they also present antigens and besides secreting cytikines and antibodies. They are also a type of APC or antigen presenting cell.

6.Alpha defensins are produced by neutrophils and Paneth cells in response to bacterial stimuli. Paneth cells are found in the base of crypts of Lieberkühn in small intestine of mammals. crypts of Lieberkühn are tubular glands found in between the villi in the small intestine of mammals.

7. cell suraface markers are used to identify cells.CD8αβ+ , CD8αα are 2 types of markers coming as subsets of CD8 marker. In humans and mice CD103 are expressed in higer levels by IEL.

8. IgA is found in blood serum in both monomeric and dimeric forms. It comprise approximately 15% of the total serum Ig. IgA in serum of blood is mainly monomeric whereas it is dimeric in form in secretions like saliva, tears, colostrums, mucus, sweat, and gastric fluid. Two monomers are cinnected by peptide bond.

9. Salmonella typhimurium is a pathogenic Gram-negative bacteria predominately found in the intestinal lumen. Salmonella typhimurium causes gastroenteritis in humans and other mammals. So thses bacteria are not commensals but pathogens.

10. Inflammatory bowel disease (IBD) is a group of intestinal disorders that cause prolonged inflammation of the digestive tract. It can include Crohn’s disease and ulcerative colitis. It can affect different parts of the digestive system and is painful and sometimes it can even turn fatal.

Risk factors associated with IBD are smoking, diet, long use of some medicines, bacterial infection of intestine, oral contraceptive pills, etc.