MLT 115 Mod 2 Les 1 pt 2

What are the specific characteristics of Natural Killer (NK) cells?

They lack traditional T and B lymphocyte markers and specifically do not possess the CD3 marker.

What is the primary function of Natural Killer (NK) cells?

To actively kill tumor cells and certain types of bacteria.

What concerns exist regarding NK cells in patients with HIV?

In HIV infection, NK cells can become dysfunctional enough to attack the patient's own cells instead of the virus.

What is the function of Human Leukocyte Antigens (HLA)?

They serve as identification markers on white blood cells, similar to blood typing antigens, and are also known as the Major Histocompatibility Complex (MHC).

What is the purpose of Cluster Differentiation (CD) markers?

To identify and genotype white blood cells at a molecular level and to facilitate necessary cell-to-cell interactions.

In which cells is the CD3 marker present and where is it absent?

CD3 is present in most lymphocytes but is notably absent in Natural Killer (NK) cells.

Where do B lymphocytes mature and what percentage of circulating lymphocytes do they represent?

B lymphocytes mature in the bone marrow and make up less than 15\% of circulating lymphocytes.

What is humoral immunity and which cells are responsible for it?

Antibody production, which is the primary responsibility of B lymphocytes.

What do B cells do when activated and what does it become?

Upon stimulation by antigens, B Cells secrete interleukins (to communicate) which helps transforms B cells into a plasma cell, which produces millions of antibodies.

Where do plasma cells reside in the body?

They reside in the lymph nodes (specifically medullary cords), spleen, and in the GALT.

What occurs during the Log Phase of the Primary Immune Response?

Clonal expansion takes place, where massive production of antibodies are produced by plasma cells.

What is an anamnestic response?

A memory component of the immune response, where memory B cells enable a faster reaction upon re-exposure to an antigen.

What are the CD marker profiles for T helper, T cytotoxic, and Regulatory T cells?

T helper: CD3+, CD4+, CD8-, T cytotoxic: CD3+, CD4-, CD8+, and Regulatory T cells: CD4+, CD25+.

Why is flow cytometry essential for monitoring HIV patients?

It is used to identify cells via CD markers and determine the CD4/CD8 ratio, which is critical for assessing disease progression.

At what CD4 count is HIV infection considered to have progressed to AIDS?

A CD4 count of less than 200 indicates progression to AIDS.

How many HLA antigen matches are typically sought for successful organ transplantation?

A match of 4-6 antigens is sought to reduce the risk of graft-versus-host disease (GVHD).

What are the six steps of the phagocytosis process performed by neutrophils?

1. Chemotaxis, 2. Adherence, 3. Engulfment, 4. Lysosome Formation, 5. Fusion, and 6. Death and Destruction.

What is the primary function of monocytes and macrophages?

They act like "garbage trucks" to clean up dead or worn-out cells and also participate in antigen presentation.

How is pus formed during an immune response?

Pus is formed from the accumulation of dead neutrophils and monocytes at the site of infection.

What substances are contained in basophils and mast cells?

Histamine and heparin, which are released during allergic reactions.

How do eosinophils respond to allergic reactions and parasites?

They detect histamine release and increase in number to suppress basophil activity; they also specifically destroy intestinal worms.

What are reactive lymphocytes and when do they appear?

They are atypical, large, irregularly shaped lymphocytes that appear during immune responses to viral pathogens like the Epstein-Barr virus (Mononucleosis).