Immunology

Immunity Is the body’s ability to recognize infectious disease causing organisms like bacteria and viruses, and protect the body from these organisms

Immunology Study of the system that fights infectious diseases

Smallpox Used to be one of the worldwide scourges But because of immunization, smallpox no longer exists in the world

Before 1979 Smallpox killed 80% of the children who contracted the virus, and about half the adults

Smallpox Since 1900, it is estimated that smallpox was responsible for 500 million deaths In 1967, the World Health Organization estimated that 15 million people contracted the disease and that two million people died in that year After successful vaccination campaign,eradication of smallpox was declared in December, 1979.

AIDS/HIV The hunt is on for a vaccine for HIV and AIDS Many millions will die from AIDS before then

How do immunizations work? Lock and key model

Antibodies are made by lymphocytes

Fab binds to antigen Fc binds to immune component

Antibodies bind to specific antigen Antigen – it can be any part of something, part of a bacteria, part of a virus that stimulates the immune system

Please do not confuse: Antigen (Ag) – any protein or structure that can stimulate an immune reaction Antibody (Ab) – Y shaped proteins that bind to antigens to mark them for phagocytosis. B lymphocytes make Antibodies

Antibody binds to antigen picture

Antibodies can be free in the blood. Antigen/Antibody complexes can signal digestion by macrophage Antigen Antibody complex picture

Antibodies can be attached to lymphocytes Ag/Ab complexes can signal the lymphocyte to reproduce making more of the same antibody Antigen Antibody complex picture

Immunization Now the body has a huge increase in the number of “receptors” that can activate the immune system in case of exposure to specific bacteria or viruses Antibody picture

Immunization So the next time the body is exposed to the specific bacteria or virus… There are already lots of antibodies to attack it

Immunity Immunity prevents infection by the increased ability for Ab to signal the destruction of the infectious organism

Serum SERUM is the liquid base of Blood It is mostly salt water

SERUM Contains small proteins called ANTIBODIES and COMPLEMENT Again antibodies are made by lymphocytes Complements are designed to attach to viruses and bacteria for phagocytosis

SERUM ANTIBODIES and COMPLEMENT attach to foreign substances such as bacteria to help the IMMUNE SYSTEM fight these substances.

SERUM Antibodies (Ab) are made by LYMPHOCYTES, a type of WHITE BLOOD CELL (WBC) Complement are proteins made by the LIVER Antibodies are very specific for antigens Complements are not specific for antigens

Plasma = Serum + Clotting Factors Clotting factors are proteins made by the LIVER Clotting factors make your blood clot - if you have no clotting factors, you would not stop bleeding from a tiny cut.

Blood Cells Red Blood Cells (RBC) - erythrocytes White Blood Cells (WBC) - leukocytes Platelets (Plt)

Blood Cells RBCs, WBCs, and Platelets are ALL made by the bone marrow During fetal development, the LIVER also makes these cells

Peripheral Blood Smear picture

WBCs – Neutrophils Neutrophils have many names Poly Morpho Nuclear Leukocytes Segmented Neutrophils (Segs) Granulocytes

WBCs – Neutrophils Neutrophils have many names: Poly Morpho

Neutrophils Picture

Granulocytes Picture

WBCs – Granulocytes There are other WBC Granulocytes besides Neutrophils - Eosinophils - Basophils

Eosinophils and Basophils Picture

Granulocytes The granulocytes contain granules These granules carry various kinds of poisons designed to kill infectious organisms That’s why people with neutropenia (too few neutrophils) are easily infected *penia – means too few

WBCs Non granulocytes WBCs that are not granulocytes are: Lymphocytes Monocytes

Lymphocyte and Monocyte Picture

Blood is made of: Substances that provide: Nutrient supply Waste removal Oxygen supply Carbon dioxide removal Stop bleeding IMMUNITY

Hematopoiesis How blood cells are made

Bone Marrow The cells we are about to see are only seen on bone marrow biopsy

The Stem Cell gives rise to 2 lines Myeloid Line - Erythrocytes (RBC) - Granulocytes - Neutrophils - Eosinophils - Basophils - Monocytes - Platelets

Lymphoid Line - Lymphocytes

Differentiation As the cells differentiate, they become different from the stem cells, and become the final product The more differentiated the cells are, the more they are like the final product

Stem Cell All of the cells of the blood begin as stem cells The stem cells divide rapidly, making not only more stem cells but cells that differentiate into their final form

Stem Cell Myeloid and Lymphoid Progenitor Picture

Lymphoid Line Picture

Plasma cell is a B lymphocyte that has been activated to make lots of antibodies

Myeloid Line picture

Granulocyte Stimulating Factor Filgrastim - Neupogen - G – CSF - this drug stimulates the body to make more granulocytes

Do not confuse G – CSF - Granulocyte Colony Stimulating Factor With: GM – CSF - Granulocyte Macrophage Colony Stimulating Factor

Body’s Defense Mechanism Everyday the body is exposed to numerous: - Bacteria - Viruses - Fungi - Parasites Our bodies are constantly fighting these organisms

Myeloid Line Neutrophils

Elevated White Count and Left Shift Seeing immature cells in the microscope we call it a left shift because in the old days laboratorians use the left hand to count using a cell counter

Reticulocytes – no nucleus - reticulated means a net-like pattern - still has parts of a nucleus Reticulocyte Count – to see if the bone marrow is making a normal amount of reticulocytes

Erythropoietin Erythropoietin is synthesized by the kidneys to stimulate the production of red blood cells

Epoetin Epoetin stimulates the production of red blood cells epoetin - Epogen - Procrit - EPO

Body’s Defense Mechanism Our bodies are really good at fighting off organisms which they encounter for the first time

Body’s Defense Mechanism Our bodies remember many of these organisms, so we can fight them even better in subsequent exposure

Immunity Immunity is the body’s ability to remember foreign substances, and attack them even better the next time

Immunity Immunity is NOT the developed tolerance to a drug, or a bacterial resistance to a drug

Picture of virus entering a healthy cell

Know that viral antigens are expressed on the surface of an infected cell The virus DNA/RNA go to the cell’s nucleus to replicate

Major Histocompatibility Complex Major – most important Histo – tissue Compatibility – how we get along Complex – not simple This is how immune cells identify self from foreign tissues

What is immunology? The production of immunoglobulins (antibodies) as a reaction of the human body when infected with an agent.

Immunoglobulins Glycoprotein molecules that are produced by plasma cells in response to an immunogen and which function as antibodies

Each immunoglobulin actually binds to a specific antigenic determinant Antigen binding by antibodies is the primary function of antibodies and can result in protection of the host

Different immunoglobulins IgG is the major Ig in extra vascular spaces Placental transfer – IgG is the only class of Ig that crosses the placenta 75% of total Ig’s

IgM IgM is the first Ig to be made by the fetus and the first Ig to be made by virgin B cells when stimulated by antigen Pentameric structure therefore IgM is a good complement fixing antibody Third most common Ig

What do we mean by immunology ? The production of immunoglobulins (antibodies) as a reaction of the human body when infected with an agent. Immunoglobulins: glycoprotein molecules that are produced by plasma cells in response to an immunogen and which function as antibodies. Each immunoglobulin actually binds to a specific antigenic determinant. Antigen binding by antibodies is the primary function of antibodies and can result in protection of the host.  All lab tests where Ag is used to detect Ab or Ab to capture the Ag, present in human specimen (blood, faeces, urine, CSF, etc. …) For Internal Use Only

What do we mean by immunology ? The production of immunoglobulins (antibodies) as a reaction of the human body when infected with an agent. Immunoglobulins: glycoprotein molecules that are produced by plasma cells in response to an immunogen and which function as antibodies. Each immunoglobulin actually binds to a specific antigenic determinant. Antigen binding by antibodies is the primary function of antibodies and can result in protection of the host.  All lab tests where Ag is used to detect Ab or Ab to capture the Ag, present in human specimen (blood, faeces, urine, CSF, etc. …) For Internal Use Only