Immunology Immunity Is the bodys ability to recognize

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 � Antigen bind to specific 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 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 � Ig. G is the major Ig in extra vascular spaces � Placental transfer – Ig. G is the only class of Ig that crosses the placenta � 75% of total Ig’s

Ig. M � Ig. M 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 Ig. M is a good complement fixing antibody � Third most common Ig

What do we mean by immunology ? ü The production of immunoglobulins (antibodies) as a reaction of the human body when infected with an agent. ü Immunoglobulins: glycoprotein molecules that are produced by plasma cells in response to an immunogen and which function as antibodies. ü 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. ü 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 7 7

What do we mean by immunology ? ü The production of immunoglobulins (antibodies) as a reaction of the human body when infected with an agent. ü Immunoglobulins: glycoprotein molecules that are produced by plasma cells in response to an immunogen and which function as antibodies. ü 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. ü 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 7 8