immunobiology lectur

8/11/2019 immunobiology lectur

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INTRODUCTION & OVERVIEW OFIMMUNOBIOLOGY

BIOLOGY 151

LECTURE 1

Marilen M. Parungao-

BalolongAssociate Professor


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OVERVIEW

OF THE

IMMUNESYSTEM

composed of two major subdivisions, the innate or non-specificimmune system and the adaptive or specific immune system

each of the major subdivisions of the immune system has bothcellular and humoralcomponents by which they carry out theirprotective function

these two arms of the immune system have distinct functions, thereis interplaybetween these systems (i.e., components of the innate

immune system influence the adaptive immune system and vice versa)


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FIRST LINE OF DEFENSE

= innate or non-specific barrier tissues such as the skin that stop the entryof organism into our bodies

IF these barrier layers are penetrated,the body contains cells that respondrapidly to the presence of the invader

EXAMPLE = macrophages and neutrophils thatengulf foreign organisms and kill them without the

need for antibodies

EXAMPLE = soluble molecules that deprive theinvading organism of essential nutrients (such asiron) and from certain molecules that are found onthe surfaces of epithelia, in secretions (such as tears

and saliva) and in the blood stream


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2ND LINE OF DEFENSE =

specific or adaptive may take days to respond to a primary

invasion (that is infection by an organism that

has not hitherto been seen)

production of antibodies(soluble proteinsthat bind to foreign antigens) and cell-

mediated responsesin which specific

cells recognize foreign pathogens and destroy

them

EXAMPLE = response in recognition anddestruction of virally-infected or tumorigenic

cells

response to a second round of infection is often more rapidthan tothe primary infection because of the activation of memory B and T cells

signals may be proteins such as lymphokines, cytokines and chemokineswhich stimulatecells of the immune system


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CELLS OF

THE

IMMUNE

SYSTEM

All cells of the immune system have their origin in the bone marrowwhichdifferentiate along distinct pathways (to discuss later)

The myeloid progenitor (stem) cellin the bone marrow gives rise toerythrocytes, platelets, neutrophils, monocytes/macrophages and dendritic

cells whereas the lymphoid progenitor (stem) cellgives rise to the

NK, T cells and B cells


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For T cell developmentthe precursor T cellsmust migrate to thethymus where they

undergo differentiationinto two distinct typesof T cells, the CD4+ Thelper cell and theCD8+ pre-cytotoxic Tcell

Two types of T helper cells are produced in the thymus the TH1cells, which help the CD8+ pre-cytotoxic cells to differentiate intocytotoxic T cells, and TH2 cells, which help B cells, differentiate

into plasma cells, which secrete antibodies


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FUNCTION OF THE

IMMUNE SYSTEM The main function of the immune system is self/non-selfdiscrimination

ability to distinguish between self and non-self is necessary toprotect the organism from invading pathogens and to eliminatemodified or altered cells (e.g. malignant cells)


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International Journal of Infectious Diseases

Volume 3, Issue 1, July-September 1998, Pages 54-60
http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%2317975%231998%23999969998%23477919%23FLP%23&_cdi=17975&_pubType=J&view=c&_auth=y&_acct=C000061230&_version=1&_urlVersion=0&_userid=8713017&md5=8c2017e602dc6fd3106d21b0868a7a94http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%2317975%231998%23999969998%23477919%23FLP%23&_cdi=17975&_pubType=J&view=c&_auth=y&_acct=C000061230&_version=1&_urlVersion=0&_userid=8713017&md5=8c2017e602dc6fd3106d21b0868a7a94http://www.sciencedirect.com/science/journal/12019712http://www.sciencedirect.com/science/journal/12019712


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!

2001 Discovery of FOXP3the gene directing regulatory Tcelldevelopment

! 2005 Development of human papillomavirusvaccine (Ian Frazer)
http://en.wikipedia.org/wiki/Human_papillomavirushttp://en.wikipedia.org/wiki/Human_papillomavirushttp://en.wikipedia.org/wiki/Ian_Frazerhttp://en.wikipedia.org/wiki/Ian_Frazerhttp://en.wikipedia.org/wiki/FOXP3http://en.wikipedia.org/wiki/Regulatory_T_cellhttp://en.wikipedia.org/wiki/Regulatory_T_cellhttp://en.wikipedia.org/wiki/Regulatory_T_cellhttp://en.wikipedia.org/wiki/Ian_Frazerhttp://en.wikipedia.org/wiki/Ian_Frazerhttp://en.wikipedia.org/wiki/Human_papillomavirushttp://en.wikipedia.org/wiki/Human_papillomavirushttp://en.wikipedia.org/wiki/Regulatory_T_cellhttp://en.wikipedia.org/wiki/Regulatory_T_cellhttp://en.wikipedia.org/wiki/FOXP3http://en.wikipedia.org/wiki/FOXP3


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INNATE & ADAPTIVEIMMUNITY

immunobiology lectur

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