Immunology: Categorization of Leukocytes ActionSIAMAK BADIE, SALIMAH CHAMPSI, FANYA GAO, DANIELLE PORTER

PHM142 Fall 2015 Instructor: Dr. Jeffrey Henderson

Leukocytes 5 Classes:

Neutrophils (40% - 75%)

Eosinophils (1% - 6%)

Basophils (less than 1%)

Monocytes (2% - 10%)

Lymphocytes (20% - 45%)

Granulocytes

Agranulocytes

Damaged Cells

Cytokines

DegranulationPhagocytosis NETs

Oxidative burst: use energy from NADPH to form oxygen free radicals

Release anti-microbial compounds

Trap microbes

Neutrophils

Characteristics:- Innate immune response- Most abundant- First responders- Granulocytes

– Mechanism of Action

Basophils – Mechanism of Action

B-philTh cell

B cell

Produce antibodies

DegranulationAllergic Response

Degranulation

Degranulation

Eosinophils – Mechanism of Action

E-philHost Defense

(Peroxidase + Rnase)Cell Activation Degranulation Degranulation

Hematopoietic Stem Cells

Ly6C -Monocyte

CDP

MDP

LP MP

Ly6C+ Monocyte

Macrophage Monocyte-Derived DC

PDCPre-CDC

PDCClassical DC

Bone Marrow

Blood

Tissue

Monocytes – Mechanism of Action

- Phagocytosis - Process and present antigen to T cell

- Process and present antigen to T cell

- Respond to viral infection- Act as APC and control T cell responses

Cellular: Cell-Mediated Humoural: Antibody-Mediated

Adaptive Immune Response

B cell T cellT & B Memory

Suppressor T Cells

Antigen

Antibodies:Signal destruction pathways

Granules: breakdown cell membrane of pathogens

Macrophage

Helper T cell

MHC

Innate Immunity: NK Cells-Non specific attack on tumours and infected cells-Release cytotoxic granules to induce cell apoptosis

Lymphocytes– Mechanism of Action

Summary

Neutrophils: Phagocytosis: use energy from NADPH to form oxygen free radicals Degranulation: secrete antimicrobial compounds Formation of neutrophil extracellular traps: trap microbes Eosinophils: Work mainly to counter infections Granules produce ROS/RNS and ribonucleasesBasophils: Work mainly in allergic responses Granules contain histamine, heparin, and antiparasitic moleculesMonocytes: Circulate in blood and differentiate into macrophages and dendritic cells in tissues during inflammation Digest pathogens and stimulate antibodiesLymphocytes: Adaptive immunity: antibody mediated B cells and cell mediated T cells attack antigen and provide antigen memory Innate Immunity: natural killer cells attack non-specifically through release of cytotoxic granules

References

1. Alberts B, Johnson A, Lewis J, et al. Molecular Biology of the Cell. 4th edition. New York: Garland Science; 2002. Helper T Cells and Lymphocyte Activation. Available from:

http://www.ncbi.nlm.nih.gov/books/NBK26827/ 2. Amulic B, Cazalet C, Hayes GL, Metzler KD, Zychlinsky A. Neutrophil function: from mechanisms to

disease. Annu. Rev. Immunol. 2012; 30: 459-4893. Bandeiro-Mela, C., & Weller, P. Mechanisms of eosinophil cytokine release. PMC. 2005; 100(1), 73-814. Falcone, F., Hass, H., & Gibbs, B. The human basophil: A new appreciation of its role in immune responses. Blood Journal. 2000; 96(13): 4028-40385. Geissmann F, Manz MG, Jung S, Sieweke MH, Merad M, Ley K. Development of monocytes, macrophages and dendritic cells. Science. 2010;327(5966):656-6616. Maddaly, R., Govind, P., Balaji, S. et al. Receptors and signalling mechanisms for B-lymphocyte activation, proliferation and differentiation- Insights from both in vivo and vitro approaches. FEBS Letter. 2010; 584(24): 4883-4894