Lecture 11 - Introduction to Immunology

8/13/2019 Lecture 11 - Introduction to Immunology

1/24

Introduction to Immunology

Dr. Linroy Christian


2/24

Introduction

Host defence can be in the form ofphysical barriers or via the immune system

The immune system is designed to protect

the body from threats External threats include pathogens and

toxins

Internal threats such as malignant cells


3/24

Externals Defences

Forms part of your innate immunity Physical barriers include:

Skin

Respiratory tract GI tract

Vagina

Other mucosal surfaces Normal flora as part of your innate

immunity


4/24

Internal Defence

Can be divided into specific and non-specific host defence

The specific or adaptive system involves

the use of antibodies and cells carryingantigen-specific receptors

The non-specific (innate) system involves

the use of circulating cells and proteins

that attack foreign material (antigens)


5/24

Organs of the Immune System

Several organs are involved in theproduction and housing of immune cells

Primary Lymphoid Organs

Bone marrow

Thymus

Secondary Lymphoid Organs

Spleen

Lymph nodes


6/24


7/24

Cells of the Immune System

Leukocytes or white blood cells defend

against foreign material and malignant

cells

Circulate throughout the body via the

blood and the lymphatic system

Can be divided into granulocytes (possess

granules) and agranulocytes (lack

granules)


8/24


9/24

Granulocytes

Neutrophil (Polymorphonuclear neutrophil) Most numerous (approx. 60-70%)

Involved in immune response to bacterial and

fungal infection

Usually the first immune cells a pathogen

encounters

Primary function phagocytosis


10/24

Neutrophil


11/24

Granulocytes

Eosinophil

Approximately 1-5% of leucocytes

Primarily involved in parasitic infections and

allergic response and asthma

Contain histamine, and enzymes such as

RNase, DNase, peroxidases and lipases

These compounds are released when theeosinophil is activated


12/24

Eosinopil


13/24

Granulocytes

Basophil

Less than 1% of cells

Contain histamine

Involved in allergic responses

Play a role in the inflammatory response


14/24

Basophil


15/24

Agranulocytes

Lymphocytes Approximately 20% of cells

More common in the lymphatic system

Comprised of T lymphocytes (T cells), B

lymphocytes (B cells) and Natural Killer Cells

(NK cells)


16/24

Agranulocytes

B Cells

Make antibodies

Activated B cells form:

Plasma cells

Memory cells


17/24

Agranulocytes

T cells

Can be divided into: Helper T cells secrete proteins that regulate

the immune response (stimulate B cells)

Cytotoxic T cells kill cells infected by viruses

and tumor cells


18/24

Agranulocytes

NK cells

Release enzymes that: Kill cells infected with viruses

Kill tumor cells


19/24

Lymphocyte


20/24

Agranulocytes

Monocyte

Approximately 6% of cells

Phagocytic

Live longer than neutrophils

Circulate freely


21/24

Monocyte


22/24

Agranulocyte

Macrophage

A monocyte that has migrated to tissue,

generally the spleen and undergo

differentiation

Phagocytic

Antigen presenting cell


23/24

Macrophage


24/24

Origin of Blood Cells

Lecture 11 - Introduction to Immunology

Documents