Immune system

General function of immune system?

Distinguish between self and non-self substances, protect organism from non-self entities

What are the primary organs/tissues of the immune system?

Bone marrow (WBC production)

Thymus (WBC maturation)

Secondary organs/tissues of immune system?

Spleen, lymph nodes, peyer’s patches in intestines, tonsils, adenoids, appendix?

What are the 3 components of innate immunity?

Surface barriers, cellular, non-cellular blood components i.e. platelets

2 components of acquired/adaptive immunity?

Cellular (T cells)

Humoral (B cells)

What are the 3 surface barriers?

Skin (mechanical, acid mantle)

Mucus (lungs, GI tract)

Body fluids (tears, saliva, stomach acid)

Innate immunity - specific or non-specific?

Non-specific, inherited, present at birth

What are the 2 components of the cellular component of innate immunity?

White blood cells (neutrophils, eosinophils, monocytes, macrophages, NK cells)

Dendritic cells (formed from monocytes, present antigens to T cells and B cells)

Acquired/adaptive immunity is specific or nonspecific?

Specific

What do B cells do?

Produce antibodies when exposed to antigen, memory cells

What do T cells do?

CELLULAR immunity, not dependent on antibodies

What are myeloid cells?

Granulocytes (Neutrophils, eosinophils, basophils)

Monocytes (precursors of macrophages, dendritic cells)

What are lymphoid cells?

T cells (helper, suppressor, cytotoxic, memory)

B cells (plasma, memory)

Natural Killer cells

Which cells are part of acquired immunity?

T cells and B cells

Antigen

Substance against which antibodies are produced

Antibody

Protein produced against an antigen

Where are B cells produced?

Bone marrow

Where are B cells activated and differentiated?

Peripheral lymphoid organ

What activates B cell?

Binding of antigen to B cell surface

What causes B cells to multiply?

T helper cell

What do B cells differentiate into?

Plasma cells or memory B cells

Plasma B cell role?

Produce antibodies

Memory B cell role?

Respond to repeated exposure to an antigen

Then differentiate into plasma cells to produce “better” antibodies

Where are T cells produced?

Bone marrow

Where do T cells mature?

Thymus

What do cytotoxic and memory T cells do?

Recognize antigen fragments on other cells surfaces and attack

What do helper and suppressor T cells do?

Regulate other parts of immune response (maintenance, keep immune system in check)

Why are T cells good for recognizing viruses?

They recognize the viral components, since many viruses do not leave a structure on the invaded cell for antibodies to detect

Role of helper T cells?

Stimulate cytotoxic T cell and B cell multiplication

Enhance macrophage function

Attract neutrophils (to site of injury)

Role of cytotoxic T cells?

Release lymphotoxins (which stimulate single cell apoptosis) into target cells to destroy them

Three main lines of defense in the immune system, in order of 1st-3rd?

Barrier, innate non-specific, learned specific

Vaccines work by…

Introduction of pathogen as an antigen, stimulating immune response of plasma cells, antibodies, etc

mRNA vaccine?

Uses protein blueprint of antigen, is faster, serves as instructions

Traditional vaccine?

Injects microbial protein or inactive microbe, is slower, components made in lab then injected to stimulate immune response

Allergy relation to immune system?

Dysregulation in the body’s ability to recognize self from non-self, the body recognizes non-pathological antigens (food, meds, pollens etc) as a threat to the body

How are allergies mediated?

Mediated by B cells, T cells, histamines (produced by basophils), other

What component of the immune system is important particularly regarding organ transplant?

Cellular. Anti rejection medications are important. But this also increases risk of infection

What happens with aging and the immune system?

Decrease in growth hormone, sex hormones, IGF-1, leading to decreased bone marrow and thymus shrinkage

What does thymus shrinkage do to T cell activation?

Decreases

Overall, what is the effect of aging on the immune system?

Slower and less robust immune response

Increased cortisol inhibits?

Lymphocyte production, also increases disease susceptibility

How does exercise affect the immune system?

Transient immune dysfunction after heavy exercise, but enhanced immunosurveillance w moderate exercise

Chronic effects of exercise on immune?

Mitigate effects of aging on immune function.