Structure and Functions of the Immune System & Immune Response MCQs

T-independent antigens can stimulate B cells directly without the need for T-cell help. These antigens are typically polysaccharides or repetitive structures that can cross-link B cell receptors, leading to B cell activation and antibody production. Key Takeaway: T-independent antigens activate B cells directly, bypassing the need for T helper cells. Tag: FMGE 2023 Tag Line: Moderate Reference: Apurva Shastri, Review of Microbiology and Immunology , chapter 12 on antigens - antibody reaction.PP-152.

Antigen-antibody interactions primarily involve ionic bonds, hydrogen bonds, and Van der Waals forces. Covalent bonds are not typically involved in these interactions. Key Takeaway: Antigen-antibody interactions are primarily mediated by non-covalent forces. Tag: May know Tag Line: Moderate Reference Apurva Shastri, Review of Microbiology and Immunology , chapter 12 on antigens – antibody reaction.PP-160.

Following antigens have poor immunogenicity (difficult induction of antibody): Smaller size/molecular weight antigens Nucleic acid > Lipids > Carbohydrates (in decreasing order) Antigens not degradable by tissue enzyme self-antigen Reference : Ananthanarayan and Paniker's Textbook of Microbiology 10th edition Chapter 15, Pg 148-150

IgG is the major serum immunoglobulin 80% of total Mol wt - 150,000 (7S) Half-life - 23 days Reference : Ananthanarayan and Paniker's Textbook of Microbiology 12 th edition Chapter 13, Pg 197-198

IgM is the first immunoglobulin developed during human fetal development at 20 weeks. Reference : Ananthanarayan and Paniker's Textbook of Microbiology 12 th edition Chapter 13, Pg 199-200

IgM antibody appears first, followed by IgA on mucosal surfaces or IgG in the serum Reference : Ananthanarayan and Paniker's Textbook of Microbiology 12 th edition Chapter 13, Pg 199-200

IgM is the first antibody produced and secreted by B cells during the primary and secondary immune responses. Reference : Ananthanarayan and Paniker's Textbook of Microbiology 12 th edition Chapter 13, Pg 199-200

IgA is concentrated in secretions and on mucus surfaces and Resistant to digestive enzymes. IgM is present in trace amounts in all secretions and does not vary considerably. IgA is the major immunoglobulin in colostrum, saliva and tears. Secretory IgA is found essentially in the superior genital tract. Reference: Jalanti R, Isliker H. Immunoglobulins in human cervico-vaginal secretions. Int Arch Allergy Appl Immunol. 1977;53(5):402-8. doi: 10.1159/000231778. PMID: 558170. Reference: Ananthanarayan and Paniker's Textbook of Microbiology 12th edition Chapter 13, Pg 198-199