Biology

Human Immunity and Blood

2,096 Questions

Human immunity and blood questions cover the physiological mechanisms protecting the body against diseases and the components of blood. Topics include blood groups, cell mediated immunity, monoclonal antibodies, and blood coagulation. These biology topics frequently appear in general science sections of competitive exams.

Blood groupsCell mediated immunityMonoclonal antibodiesBlood coagulationCancer immunology

Human Immunity and Blood Questions

Multiple choice

S3 stands for pneumococcus polysaccharide SIII. In a lymph node, the antigen pneumococcus polysaccharide SIII causes

  1. lymphocyte proliferation in the paracortex

  2. PALS development

  3. proliferation in cortical lymphoid follicles

  4. development of cellular hypersensitivity

  5. the absence of germinal centers
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Stimulation of antibody-formation by this thymus-independent antigen leads to proliferation in this location with development of germinal centers while the paracortical region remains inactive, reflecting the inability to develop cellular hypersensitivity to the polysaccharide.

Multiple choice

Expression of a CD8 alpha-alpha homodimer is characteristic feature of ____________.

  1. follicular dendritic cells

  2. intraepithelial lymphocytes

  3. eosinophils

  4. classical cytotoxic T-lymphocytes

  5. classical helper T-lymphocytes
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

CD8 alpha-alpha homodimers are almost exclusively found on intraepithelial lymphocytes and may restrict these cells to recognition of certain nonclassical MHC molecules, perhaps including TL and Qa1.

Multiple choice

Which among the following is a distinctive feature of B cells?

  1. Class I MHC

  2. CD3

  3. Measles virus receptor

  4. Polyclonal activation by concanavalin A

  5. Surface immunoglobulin
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

B-cells express surface immunoglobulin of a specificity created by that cell's particular immunoglobulin gene recombination. A totally different gene set encodes the T-cell receptor for antigen.

Multiple choice

Which of the following cells do not have nuclei?

  1. White blood cells

  2. Red blood cells

  3. Platelets

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Mature mammalian red blood cells (erythrocytes) lose their nuclei and other organelles to maximize space for hemoglobin, which carries oxygen.

Multiple choice

Stem cell factor is produced mainly by

  1. thymic epithelium

  2. the bone marrow stromal cells

  3. stem cell

  4. megakaryocytes

  5. reticuloendothelial system
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The bone marrow stromal cells comprise a complex mixture of cells including fibroblasts, macrophages and various other cell types. Stem cell factor (SCF) remains associated with the extracellular matrix and acts on primitive stem cells through a tyrosine kinase membrane receptor.

Multiple choice

The circulating plasma protein which participates in the initiation of blood coagulation is known as high molecular weight kininogen (HMWK). Which of the following is the other name of HMWK?

  1. FSF

  2. AHF

  3. Proaccerin

  4. Hageman factor

  5. Fitzgerald factor
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

High molecular weight kininogen is also known as Fitzerland factor. In the past, HMWK has been called HMWK-kallikrein factor, Flaujeac factor (1975), Fitzgerald factor (1975) and Williams-Fitzgerald-Flaujeac factor, the eponyms being for people first reported to have HMWK deficiency. Its current accepted name is to contrast it with low molecular weight kininogen (LMWK), which has a similar function to HMWK in the tissue (as opposed to serum) kinin-kallikrein system.