HPRS 2201 Chapter 3 Immune

Added: 2026-06-02

[00:00:00]Today we're going to talk about immunologic diseases and conditions. The major functions of the immune system are to protect the body against foreign organisms, maintain homeostasis by eliminating damaged cells in phagocytosis, battles infection, and recognizes self from non-self and defends the body from non-self. So we have inappropriate responses of the immune system. We have hyperactive, which is an allergic; this is an excessive response so allergies and things such as asthma, and this is an immediate hypersensitivity with IgG and the allergens. Immunodeficient - AIDS for example. This is an inadequate response. Autoimmune such as systemic lupus erythematosus is a misdirected response, and a transplant rejection attacks beneficial foreign tissue and that's cell-mediated immunity. Now these are the different types of acquired immunity. So we can have, let me see if it's gonna let me write on this, hold on. There we go - text box okay. So this, I'm not doing too well with this. This is natural okay, and this is artificial. This over here. So this a way is active, and the last one is passive.

[00:02:38]OK guys so natural active okay now first of all if it's active you get the antigen, and you make the antibody. If it's passive. they are giving you the antibody okay. So natural/active - you contract the disease, and you produce memory cells okay. In artificial you also produce memory cells, but you get a vaccination but YOU are producing the antibody. And in passive, so passive/ natural - that's the that when the babies get the maternal antibodies through the placenta or breast milk, and in passive/ artificial they're giving, just giving you antibodies like IV immunoglobulin or something like that okay, but they're giving you, this bag has antibodies in it.

[00:03:47]They talk about CD cells. Those are clusters of differentiation, and all they are are cell surface markers; they're antigens. T lymphocyte cells include cytotoxic T cells, which destroy virus-infected cells, tumor cells, or allograft cells, and those are called CD8 cells. Helper T cells stimulate B-cells and active cytotoxic T cells, and these are CD4. Suppressor T cells moderate the immune response by inhibiting B and T cells, and memory T cells are reactivated only by re- exposure to the previous antigen.

[00:04:29]B lymphocytes include memory B cells and plasma cells, and those plasma cells secrete antibodies.

[00:04:40]These are your different immunoglobulins. You have your IgG, IgA, IgM, D and E. That IgD has a receptor site on the B cell and binding with the antigen activates the B cell. So you have your primary response, and that's with an IgM antibody and type, and then your secondary response is an IgG. Now this is just compliment fixation. Remember you start off with that C4AC2B, and it winds up the beginning of the MAC (the membrane attack complex) okay that destroys the cells. So activation of normally inactive proteins found in plasma or body fluids, pathogens are destroyed by lysing of the cell membrane or phagocytosis. Now let's talk about some immunodefficiency diseases.

[00:05:44]These are increased susceptibility to a bacterial infection infections resulting from a B-cell deficiency, increased susceptibility to viral, fungal, and protozoan infections usually from a T-cell deficiency. Acquired Immunodeficiency Syndrome or AIDS. This is a progressive impairment of the immune system caused by HIV (the human immunodeficiency virus). Many organ systems are affected and ultimately life-threatening. You see where is my 24?

[00:06:22]Ah this capsid protein, this p24 okay, this is part of the capsid. Let's see what else. This right here, this transmembrane glycoprotein this gp41 gp120 okay enables the virus to fuse to target cells and it binds to CD4 cells.

[00:06:48]There's a reverse transcriptase in there okay.

[00:06:52]This copies single-stranded RNA to complimentary DNA. In AIDS you have decreased CD4 and increased virus and p4.

[00:07:11]In immunodeficiency diseases HIV transmission is through direct contact with blood or semen of infected person through sexual contact, blood transfusions and other blood products, contaminated shared needles, accidental needle sticks, or to the fetus via placenta or during birth process from infected mother. You want to make sure that you practice universal precautions because you can't tell if somebody is infected with the HIV virus or hepatitis virus for that matter, but sometimes you can if it's the later stages, but not in the beginning. Thorough and frequent hand-washing, personal protective equipment, proper disposal of all sharps (never, ever, ever recap a needle ever), caution in handling of laboratory specimens, proper containment and disinfection of blood and bloody body fluid spills, and use clean mouth pieces and resuscitation bags. Now we'll talk about several other immunodeficiency diseases. The first one is the common variable immunodeficiency. This is an acquired B-cell deficiency. You have low levels of antibodies, which makes, gives you an increased susceptibility to infection. It's also called acquired hypogammaglobulinemia. Now some people with this deficiency have decreased IgG and IgM or they may have a decrease in IgG IgM and IgD.

[00:08:51]So this acquired B-cell deficiency results in an absence of antibody production or function. Most patients have a normal number of B lymphs, but fail to undergo normal maturation into plasma cells, which turns into immunoglobulins and antibodies. Selective immunoglobulin A deficiency. This is an inadequate production of IgA. Primarily IgM and IgG protect us internally from infection. IgA is primarily found in secretions. IgA antibodies are transported to the mucosal surfaces such as the eyes, ears, nose, GI tract where they protect these surfaces from infection. Typically these people are asymptomatic. Now you have to, one thing you do have to worry about people with Selective Immunoglobulin A deficiency - when they get fresh frozen plasma, they you have to give them FFP with another person who has this Immunoglobulin A deficiency okay because they will make antibodies to the IgA in the donor FFP so you got to be careful. The last one is the Severe Combined Immunodeficiency. This is an ineffective development and function of both the T cells and the B cells. DiGeorge's Anomaly. OK this, the pharyngeal pouches that you see, these are the third and fourth pouch the third one is becomes the inferior parathyroid glands and the thymus, and the fourth is the superior parathyroid glands and the pair of follicular cells of the thyroid gland. Pharyngeal pouches - one of the paired sacculations in the lateral aspect of the pharynx in vertebrate embryos okay. This is also called thymic hyperplasia or thymic aplasia. It's an immunodeficiency; you have a small or absent thymus. The clinical syndrome results from a congenital development field defect with malformation of the third and fourth pharyngeal pouches. Patients have a variable T cell deficiency resulting from faulty embryonic development of the thymus and parathyroid glands. These are two DiGeorge's anomaly okay.

[00:11:32]Infection is the primary problem and it leads to an early death okay. In this hypocalcemia, well the hypoparathyroidism accounts for the hypocalcemia and that's bad because it can lead to tetany where your muscles just constrict, constrict, constrict. The diagnosis of DiGeorge's anomaly is a decreased T-cell and two of the following: they have a cardiovascular defect (most of the time it's tetralogy of Fallot), hypocalcemia of greater than three weeks, and a microdeletion involving chromosome 22.

[00:12:19]Now this deletion right here, that's when part of a chromosome or a sequence of DNA is missing so you have a loss of genetic material. That loss of the TXB1 gene, see the one in red, is probably responsible for the heart defects cleft palate, distinctive facial features, hearing loss, and decreased calcium levels. The loss of the COMT gene, which is the next one, you have an increased risk of behavior problems and mental illness. Chronic Mucocutaneous Candidiasis. This is a group of disorders characterized by a persistent and recurrent Candida infections of the skin, nails, and mucous membranes. So they're okay with everything else; they just the candida got'em. The Wiskott-Adrich Syndrome is a congenital disorder. There's an inadequate T and B cell function. They have short-lived platelets and incompetent phagocytes, and it's the the WASP. it's the Wiskott-Aldrich Syndrome Protein. Now we're going to talk about some autoimmune diseases. Lymphocytes and antibodies are sensitized to develop against the body's own organs or tissues so they lose that concept of self versus non-self. May be triggered by disease, injury, metabolic changes or mutations in immunologically competent cells. May be caused by certain drugs or chemicals, trauma, or viral infection. Autoimmune diseases develop when auto- antibodies develop and begin to destroy the body's own tissues. And tolerance to self-antigens is believed to commence.

[00:14:17]during fetal life. Autoimmune Hemolytic Anemia. This is an autoimmune condition in which red cells are destroyed by antibodies. There two types: warm autoimmune hemolytic anemia and cold autoimmune hemolytic anemia. So you treat the warm with corticosteroids and cytotoxic drugs and cold autoimmune hemolytic anemia you want to avoid the cold. And another thing you can do is a plasmpheresis to take out the antibodies. Now there are two types of antibodies in the warm hemolytic. They're IgG in nature and they react at 37.

[00:14:58]Certain drugs can cause it such as penicillin. Autoimmune diseases such as lupus or malignancies such as CLL can cause it, and the cold hemolytic anemia that's IgM in nature and reacts best at 30 degrees. There's complement fixation of the IgM on the red cells. It's usually brought on by infectious mononucleosis or Mycoplasma pneumoniae.

[00:15:32]Pernicious anemia is impaired absorption of B12 and B12 deficiency due to decrease gastric production of hydrochloric acid and a shortage of intrinsic factor. So you have absence of the intrinsic factor secondary to gastric atrophy. Now this is just something to show you what's going on in pernicious anemia. So ninety percent of them have anti-parietal antibodies, which are cytotoxic to parietal cells and these are large cells on the margins of the gastric glands of the stomach and they secrete hydrochloric acid and intrinsic factor. Treatment is lifelong intramuscular injections of vitamin B12 okay so let me go through this real quick and again I'm not going to test you on it I just want you to know about it. Vitamin b12 is released from food by peptic digestion at a low pH in the stomach and that binds to an R-binder, and this is just a protein secreted in the saliva and stomach. Then vitamin B12 is released from the R-binder in the duodenum (the pancreatic proteases degrade the R-binding protein). The released vitamin B12 binds to the intrinsic factor. Intrinsic factor-vitamin b12 complex binds to intrinsic factor receptors in the mucosal cells of the ileum. When vitamin B12 leaves the mucosal cells of the ileum, it is picked up by the transporter proteins in the blood and those are the transcobalamin one and two, and it's taken up by cells in the liver, bone marrow, and other dividing cells that have specificTC-2 receptors. Then the transcobalamin-2 degrades and inside the cell, vitamin B12 is released and utilized. Idiopathic thrombocytopenic Purpura. Sometimes it's called immune thrombocytopenic purpura. The immune system produces antibodies against the platelets. This is an acquired disorder that results from an isolated deficiency of platelets. It's more common in children than adults. If you notice multiple bruises on a child or adult that can't be explained, seek medical attention.

[00:18:01]Platelets are destroyed in the spleen Platelet auto-antibodies found in most cases. It's usually self-limiting; may occur after a viral infection, and the spleen may destroy damaged platelets. The next one is immune neutropenia. There's a decreased number of circulating neutrophils usually due to anti- neutrophil antibodies. The treatment for severe cases: corticosteroids, immune globulin, G-CSF, antibiotics, transfusion of white blood cell concentrates.

[00:18:39]G-CSF is granulocyte colony stimulating factor. Goodpasture's Syndrome. OK so this is a cross-section of a normal glomerular capillary, and this little endothelial cells and stuff like this. This is also called anti-GBM disease - glomerular basement membrane disease. It's autoimmune. There are antibodies directed against an antigen in the glomerular basement membrane. It affects the basement membrane in the kidneys and the lungs okay. It can be caused by genetics, viral infections, exposure to certain chemicals such as hydrocarbon solvents and Paraquat, which is a weed killer. So the inner surface right here is lined with endothelial cells that sit on the basement membrane, and so they have antibodies against that basement membrane. Now anti, these antibodies in the kidney, so anti-GBM in the kidneys, it's called anti-GBM glomerulonephritis. In the lungs it's called anti-GBM alveolar capillaritis, but if you have both, that's when you have Goodpasture's. Systemic Lupus Erythematosus.

[00:20:05]These are collagen connective tissue diseases. This is a chronic, inflammatory, autoimmune disease. Unusual antibodies in the blood that target tissues of the body. It mostly affects women in their 20s and 30s. Now this is a discoid lesion.

[00:20:26]We always talk about that butterfly rash, but these are also lesions okay. So you have butterfly face rash, discoid lesions, fever, fatigue, joint pain, malaise, joint deformities, weight loss, Raynaud's phenomenon, and hair loss. Raynaud's is when the extremities are, they'll turn color. They'll either blanch or turn blue in the cold. Scleroderma - this is an autoimmune disease. It's hardening of the skin and connective tissue. It's a chronic, progressive disease characterized by sclerosis or hardening, Scarring of internal organs may also occur. Is an overproduction and accumulation of collagen in the body tissues. The immune system turns against the body, producing inflammation and overproduction of collagen.

[00:21:27]Sjogren's syndrome - this is an autoimmune disease and inflammation in various glands of the body. Result is dryness in affected area. So the dryness, that's Sjogren's. Rheumatoid arthritis. It attacks the synovium. It's a chronic inflammation and edema of the synovial membrane surrounding the joints. Destruction of cartilage and adjacent bone, joint pain and stiffness especially in the morning.

[00:22:00]It's actually a systemic disease not just to the joints.

[00:22:03]OK now osteoarthritis up here only affects the bones in the joints not that synovium. Rheumatoid arthritis the treatment is aimed at reducing inflammation and pain, preserving the joint function, and preserving, preventing joint deformities. So they do that by medication, rest, special exercises, and joint protection. It affects the ball and socket joints. The cartilage gradually erodes.

[00:22:37]Ankylosing spondylitis. Ankylosing is to to ankylos is to fuse. This is an immune response directed at joint tissue. Systemic, progressive inflammatory disease primarily affecting the spinal column. The vertebrae fuse together; it makes the spine less flexible. As the condition worsens and the inflammation persists, new bone forms as part of the body's attempt to heal. This new bone gradually bridges the gap between vertebrae and eventually fuse a section of the vertebrae together.

[00:23:15]Polymyositis - this is autoimmune, inflammation of the muscle fibers.

[00:23:21]Primarily affects those closest to the trunk or torso and results in severe weakness and ones in red, the muscle groups in red, are the ones primarily affected in polymyositis.

[00:23:40]Multiple sclerosis. This is an inflammatory disease of the central nervous system. It attacks the myelin sheath. Ultimately causes scarring that debilitates the nerve. Remember the myelin sheath is a protective covering that surrounds the nerve cell. The nerve damage is caused by inflammation. When the nerve covering is damaged, the nerve impulses are slowed or stopped. Treatment for diagnosed relapsing remitting multiple sclerosis may include interferon beta 1 alpha or beta 1 a, which is Avonex.

[00:24:24]Myasthenia gravis. This is a chronic, progressive neuromuscular disorder. Antibodies are produced to the acetylcholine receptor in muscle cells. Patients experience extreme muscular weakness and progressive fatigue. So thus acetylcholine, which is a neurotransmitter, can't get to the muscles because the auto-antibodies are blocking the receptor. Small vessel vasculitis. This is an inflammation of the walls of the blood vessels, and it apparently affects the capillaries, arterioles, and venules. And the last slide is systemic necrotizing vasculitis. Is inflammation again in the walls of the blood vessels, but this one primarily affects medium and large arteries, and that's it. Thank you.