Immune System

Granulocytic Leukocytes

Neutrophils, basophils, eosinophils

Agranulocytic leukocytes

Monocytes which differentiate into macrophages, dendritic cells, and lymphocytes

Neutrophils

Most common of white blood cells and active in the initial stages of infection

• Can exit blood and enter infected tissue

• phagocytic

Basophils

Release components promoting inflammatory & allergic responses (histamine)

Eosinophils

phagocytic & exit blood; release toxins and often deal with large multicellular pathogens

Macrophages

eat pathogens and clear out dead cells

Dendritic cells

Essential for adapting immunity as they capture antigens from pathogens and present them to T cells

Lymphocytes

B cells, T cells, and natural killer cells

Natural Killer cells

kill infected body cells & some tumor cells; recognizes abnormalities in the plasma membranes which signal it ot kill that cells

T cells

modulates specific immune responses

B cells

produce antibodies to bind antigens

Mast cells

assist with allergic and inflammatory responses

• Contains histamine which make blood vessels dilate and more permeable to allow white blood cells to reach affected area

Cytotoxic T cells

destroy infected cells by causing apoptosis

Helper T cells

help activate other white blood cells

IgG

most abundant type of antibodies. Enhances phagocytosis, neutralizes toxins, trigger complement system

IgA

Mucosal immunity

IgM

1st antibody produced in response to infection. Forming complexes w/ antigens and activating complement

IgE

allergic reactions and parasitic infections

IgD

less understood antibody role in initiating early immune response

• Produced by B cells