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NEET Questions / Zoology / Biology and Human Welfare / Immunity
A patient presents with chronic mucocutaneous candidiasis. Genetic testing reveals a defect affecting the development and function of T helper 17 (Th17) cells. Which cytokine is MOST likely directly impacted by this genetic defect?
IL-4
IFN-Ξ³
IL-10
IL-17
A novel immunodeficiency is characterized by recurrent bacterial infections, particularly with encapsulated bacteria. Serum analysis reveals normal levels of IgG, IgM, and IgA, but significantly reduced levels of complement component C3. Which pathway of complement activation is MOST likely primarily affected?
Classical pathway
Lectin pathway
Alternative pathway
Terminal pathway
Which of the following accurately describes the role of HLA-E in immune regulation?
Presents antigens to CD8+ T cells
Activates NK cell activity
Stimulates antibody production by B cells
Inhibits NK cell activity
A mutation in the gene encoding the autoimmune regulator (AIRE) protein is MOST likely to result in which immunological consequence?
Increased susceptibility to bacterial infections
Impaired isotype switching in B cells
Defective T cell development in the thymus
Development of autoimmunity against tissue-specific antigens
A research study investigates the immune response to a novel viral pathogen. It is observed that neutralizing antibodies are generated within the first week of infection, but cytotoxic T cell responses are delayed, appearing only after two weeks. Which of the following is the MOST likely explanation for this observation?
The virus infects and depletes T cells initially.
The virus evades MHC class I presentation, delaying CTL responses.
Antibody responses are T-independent while robust CTL responses require T cell help.
The virus replicates primarily in B cells, promoting antibody production.
Individuals with defects in the C1 inhibitor protein are prone to hereditary angioedema. Which of the following BEST describes the underlying mechanism of this condition?
Defective phagocytosis by neutrophils and macrophages
Impaired antibody production by B cells
Overproduction of histamine by mast cells
Unregulated activation of the complement system leading to increased bradykinin production
Which of the following is NOT a part of the innate immune system?
Skin
Mucous membranes
Antibodies
Natural killer cells
What is the primary function of phagocytes?
Produce antibodies
Activate T cells
Engulf and destroy pathogens
Release histamine
Which type of immunity is acquired through vaccination?
Passive natural immunity
Active natural immunity
Passive artificial immunity
Active artificial immunity
Which cells are responsible for producing antibodies?
T cells
Macrophages
B cells
Neutrophils
