HSF II Histology Leukocytes Flashcards
Role of chemotaxis and cytokines for WBCs
WBCs are attracted to infection sites by chemical signals, specifically cytokines from dead/damaged cells or pathogens
How do leukocytes leave the bloodstream?
Adhesion is strong with ICAMs
Margination, (tethering before) pavementing (rolling/adhesion), diapedesis
What is the extravasation and homing mechanism?
Extravasation is the process of WBC moving out of the capillary into tissue. The homing mechanism is how WBCs get where they need to go
Describe primary granules
Azurophilic
Present in all WBCs
Contain lysosomal enzymes (hydrolases)
Describe secondary granules
Lysozyme and alkaline phosphatases
Variable staining
Acquired immunity consists of…
B cell lymphocytes for germs
T cell lymphocytes for compromised cells in the body
APCs to alert lymphocytes to foreign agents
Describe neutrophils for acute inflammation (w/in a week)
note:
Cardinal signs of inflammation:
pain, swelling, redness, heat
PMN (polymorphonuclear)
Pale-colored granules
Eliminate bacteria/ limit inflammatory extent
Phagocytotic primarily, phagolysosome, respiratory burst (H2O2, HOCL)
Elastase, myeloperoxidase in pr1mary
Lysozyme, proteases, defensins, lactoferrin in 2ndary (all antibacterial stuff)
Gelatinase in 3rtiary to break down collagen
Homing and neutrophils
Have receptors for integrins (to bind to iCAMs) to enable antibacterial fxn and homing of neutrophils
What are stab cells or band cells?
Immature neutrophils (do not appear multilobed)
Deeply indented (>1/2) nucleus
Increased numbers of these = left shift
Describe eosinophils
IgE surface receptors
Parasitic infection role
Reduce allergy severity (inhibit basophils)
Triggers bronchial asthma
Histaminase, Eosinophil peroxidase, Lysosomal enzymes, Major basic protein (against heparin + parasites)
Use eosinophilic chemotactic factor to go to basophils and mast cells to ameliorate histamine
Releases eosinophil-derived inhibitor to inhibit basophil and mast cells
Antiparasitic against helminth and affinity for Ag-Ab complexes (destroyed by major basic protein, phagocytosis)
Describe basophils
Least numerous granulocyte
Many BV granules in cytoplasm
May resemble mast cells in leaving circulation
Hydrolytic enzymes, heparin sulfate (anticoagulant), histamine (increases vasodilation and permeability)
Leukotrienes–> slow reacting anaphylaxis
Degranulated for Type 1 hypersensitivity (asthma, allergy), and can escalate to anaphylaxis
Describe mast cells
Resident cell in CT w/ histamine and heparin
Part of immune and neuroimmune lines
Allergy, anaphylaxis, wound healing, angiogenesis, pathogen defense
In the bone marrow, monoblasts…
turn into promonocytes in vascular niche and exit via venous sinuses to become macrophages (filled w/ hydrolytic enzymes) that will phagocytose bacteria, present antigens, and clean up debris
Macrophages and lymphocytes are active in…
subacute to chronic infections
Macrophages can fuse and…
become multinucleate epitheloid granulomas (chronic)
B-cells come from ___ _____ in mammals and function in…
bone marrow;
humorally mediated immune response and produce antibodies
they encounter Ag and undergo clonal expansion to produce Ab-producing plasma cells
B-cells also function in the anamnestic response of humoral immunity, which means…
renewed rapid production of antibodies following the second contact with antigen (vaccine stuff)
B-cells also can…
present Ag and have HLA type 2 surface markers and surface immunoglobulins
Plasma cells have a ____ nucleus and are…
Cartwheel; activated B cells that make large amts. of a specific antibody
T-cells are also formed in bone marrow but migrate to…
Thymus to become immunocompetent. Cell-mediated immunity with paratopes (receptors like Ab) and recognize epitopes on Ags
Have CD (cluster of differentiation) markers/molecules on surface to recognize HLA (human leukocyte antigen) receptors to prevent self-destruction
What are the types of T-cells?
Cytotoxic - kill cells w/ foreign surface Ags
Helper - sound chemical alarm (usually presented by macrophage/b-cell) by secreting cytokines to stimulate B-cells to make AB or Tk to kill
Suppressor - suppress B-cells to dampen immune response (to self molecules)
What are null cells?
Note- FC receptor is found on cells that protect the immune system. They bind to FC part of antibodies attached to pathogens.
Neither B or T cells, they have Fc receptors without markers
Include natural killer cells and pluripotent stem cells that can be cytotoxic and help in AB-dependent cytotoxicity (ADCC)
Lymphocyte maturation process
Lymphoblast->Prolymphocyte->Lymphocyte
Mature B-/T-Cells leave bone marrow and thymus to establish lymphocyte colonies in…
the spleen, gut, and lymph nodes
