Immunology Practice Questions

• The immune system identifies pathogens as foreign and provides protection against diseases
• Immunology studies the immune system in states of health and disease, dealing with its malfunctions
• Serology studies antigen-antibody reactions
• A properly functioning one recognizes self versus non-self

Malfunctions of the Immune System

• Autoimmune diseases occur when the body attacks its own antigens with autoantibodies, SLE is a common example in females
• Hypersensitivities are immune overreactions; type 1 includes allergic reactions
• Immunodeficiency involves the loss of the capability to distinguish self from non-self
• Immunocompromised individuals (e.g., those with HIV) are examples
• Geriatric immunodeficiency occurs after age 65 due to immunosenescence as chromosomes shorten with mitosis, and G1 becomes G0
• Pediatric immunodeficiency occurs because infants under 6 months have diminishing maternal antibodies and an underdeveloped immune system
• Transplant rejection occurs when the graft tissue attacks the host (graft vs. host) or the host attacks the graft (host vs. graft), and is exemplified by blood transfusions

Types of Immune Systems

• Innate immunity provides a non-specific, localized inflammatory response for protection, marked by redness, swelling, heat, and pain
• Adaptive immunity provides a specific antibody response dependent on the antigen

Complement Proteins

• Complement proteins are native proteins in blood circulation that induce inflammation as a response against pathogens
• In autoimmune diseases, complement is consumed
• An example of their function would be B anti-A antibody + A antigen + complement = immune complex which then leads to lysis → hemoglobin release → death
• B anti-A antibody + A antigen can also lead to agglutination

Epithelial Barriers

• Impenetrable skin with waxy keratin
• This is only as long as it remains intact

Phagocytes

• Mononuclear phagocyte system (MPS) cells, such as macrophages, are examples
• Lysozyme targets PDG Gram (+) and is found in saliva and tears
• Antigen-presenting cells (APCs) are highly phagocytic cells that encounter invaders first and function in both innate and adaptive immunity
• APCs process foreign substances in lysosomes, fragmenting them into antigens coupled to MHC class II, and present these to T-cells
• Macrophages, dendritic cells, and mast cells are examples of APCs

Other Cells

• Neutrophils are another cell type
• Natural killer cells are lymphocytes with granules that automatically destroy virally infected and cancerous cells
• Gastric acid is also a part of the immune system

Adaptive Immunity

• The specific antibody response depends on the antigen, such as anti-hepa B antibody targeting hepa B antigen
• All antibodies are immunogammaglobulin
• Lymphocytes can be distinguished but T-cells versus B-cells cannot be differentiated in peripheral blood smears, with Wright-Giemsa being the best stain for blood

T-Cells

• T-cells are cell-mediated and mature into effector T-cells
• When MHC class II tag is recognized, lymphoblasts enlarge and proliferate to amplify the immune response
• T-cells, along with basophils, mast cells, and dendritic cells, are generated in bone marrow and mature in the thymus
• Helper T-cells (TH) upregulate the immune system; immunocompetence is balanced with a 2 TH to 1 Ts ratio, with low numbers or reversal indicating immunodeficiency
• Suppressor T-cells (Ts) downregulate gene expression
• Cytotoxic T-cells (TC) are analogous to NK cells, activated by antigens to destroy virally infected and tumor cells

B-Cells

• B-cells utilize antibodies, and are part of the humoral (liquid) immunity
• Generated and mature in bone marrow but in birds, B-cells mature in the bursa of fabricius

Additional Information

• Serum is the liquid after blood has clotted, while plasma is the liquid with an addition of anticoagulant
• Leishmania can survive inside highly acidic environments like lysosomes

Blood

• Hematopoietic stem cells are multipotent/pluripotent cells found in bone marrow, where all IS cells originate
• Lymphoid stem cells mainly produce adaptive immunity, while myeloid progenitors produce natural immunity
• Histiocytes are specifically tissue macrophages

RBCs/Erythrocytes

• Most abundant due to the need to carry oxygen
• Biconcave and anucleated for efficient oxygen distribution
• Never used for genetic analysis
• During erythroblast maturation in bone marrow, the nucleus is lost before release into peripheral blood
• Hematologists visit if nucleated RBCs are present
• Males have 5.5L due to having an abundance of androgen
• Erythropoietic
• Females have 4.5L resulting from having low androgen and menstruation
• Lifespan for 2-3 months
• Near death, change osmotic pressure becomes permeable, causing water to enter, and the cell to burst when dead, it then releases hemoglobin

Hemoglobin

• Heme is ferrous (Fe+2) + protoporphyrin
• Mostly recycled
• Excess stored in ferritin (a protein) in the liver as ferric (Fe+3)
• Becomes bilirubin (yellow pigment)
  • LB1 has cyanotic reactions and inabilities to get oxygen, and it is also jaundice
• Globin (protein) is then recycled
• High RBC indicates erythrocytosis
• Low RBC then indicates anemia
• Erythroblastosis is a complication for newborns
• Rh female + Rh+ male leads to an alive and Rh+ first born which creates anti-Rh that is neutralized by RhoGAM, then attaching to make sure to prevent lysis, resulting in an attacked 2nd child
• Majority of Filipinos are Rh+
• ABO compatibility will results in mild effects because of the IgM pentamer

Platelets/Thrombocytes

• 150,000-400,000 per µL
• Not true cells, but remnants of megakaryocytes granules and cytoplasm
• Grows by 4x in size
• Located only in bone marrow and is anucleated, but has mtDNA

WBCs/Leukocytes

• Lowest in count
• Visit immunologist with high/low count results
  • -philia is high WBC
  • • penia is low WBC

Granulocytes

• Eosinophil is bilobed with red-orange granules in cytoplasm
• High eosinophil indicates asthma or parasitism resulting in Charcot Leyden crystals that also cause perennial cough and cough
• Basophil is bilobed with blue-black granules in its entire cell
• Mast cell also is a tissue basophil
• High basophil means allergic reaction
• Neutrophil has pinkish, azurophilic granules
• Usually has 2-3 lobes
• First line of defense
• Microphage in presence of antigen
• High neutrophil indicates bacterial infection

Agranulocytes

• Lymphocytes have high nucleus to cytoplasmic ratio with large and compact nucleus for favorable genetics analysis
• Found in lymphoid tissue, blood, and organs
• Act as receptor for specific antigens, and meditate adaptive immune response
• For DNA tests and identity analysis

Other

• High lymphocytes indicates immunodeficiency or viral infection
• Monocytes are the largest WBC in peripheral blood with a horseshoe or kidney shaped nucleus
• Macrophage in presence of antigen
• Fill in wounds in areas that have collagen and almost healed, along with amorphous
• High monocyte indicates the body has TB, or bacterial infection

Organs of the Immune System

• The primary lymphoid organs are the bone marrow (replaced by fetal liver as we age) and the thymus (atrophies/decreases in size as we age)
• Secondary lymphoid organs like lymph nodes are where APCs proceed for activation to introduce T-cells, causing swelling and cytokine release to activate other lymphocytes; lymph nodes have lymph vessels carrying lymphatic fluid (water) and lymphocytes
  • Swollen in the back of ear or neck indicates weak lungs
  • Swollen at armpit indicates breast infection
  • Swollen at groin indicates STI
• Other secondary lymphoid organs include the tonsils (adenoid organ), spleen (filters blood, distributes T- and B-cells, graveyard of blood), gut-associated lymphoid tissue (with probiotics, phagocytes, and immune cells), and cutaneous-associated lymphoid tissue

Antigen and Antibody

• Antigens are any substances that initiate antibody protection
• Immunogen specifically elicits immune response
• The more foreign and complexed an antigen is in the animal, the more immunogenic it is
• Chemical nature: proteins are preferable over CHO
• CHO usually has epitope

Antibodies

• FAB binds to antigen
• Requires adjuvant to make light antigen be useful for the body
• Made from fragments of antibody binding size
• Antibody structure is often characterized by X-ray diffraction/crystallography
• Myeloma protein causes multiple myeloma which leads to abnormal proteins that can lead to cancer

Types of antibodies

• IgG: 150,000 Da

  • Can cross placenta
  • Hemolytic disease can occur
  • Anamnestic response will occur with boosters
  • Most 80% of Ig

• Serum lgA: 160,000 Da

  • Protection from mucosa
  • Main homeostasis
  • lgD: 180,000 Da
  • Found when there is Hepa D

• lgE -180,000-200,000 Da

  • linked to reaction
  • Can be a dimer and secretory

• lgM: 900,000 Da

  • Cannot cross the placenta
  • Acute and recent encounters

Other Notes

• Overview of the stages of immune response: It begins with antigen recognition → follows with a natural then an adaptive response
• Microbial invasion/priming is the 1st major point, the 2nd is microphage
• B-cell has resistance to microbial outbreaks due to its first engagement

Allergies(Type 1 Hypersensitivity)

• Itchiness (pruritus) and bumps on skin
• Due to release of basophil granules and vessel dilation
• Drop in BP then will results in anaphylactic shock
• Pantal is for quick fixes
• Sensitization allows antigen coating
• Desensitization familiarizes the consumption
• Histamine causes cardial Wheal leading to allergic reaction
• Treated by antihistamine

Antigen - Antibody Reactions

• Agglutination will form clogging and aggregation with insoluble antigens
• Agglutinin: IgM binding to antigen
• Precipitation works with soluble antigens
• Precipitation requires an equal no. of antigens, not more or none, in order to be affective, with potential serial dilutions to get to the maximum results to determine the negative
• Antibody then nullifies the toxic level to antigens with the need of complement to fully activate it

Other Notes

• The enzyme Pepsin - Cleaves below the hinge region, producing F(ab')2 and an Fc fragment.

• The enzyme Papain - Cleaves above the hinge region, producing two Fab fragments and an Fc fragment.

• Rh - IgG has lambda and kappa for all kinds, both not ever present in both antibodies, but they can each independently in the people

• Requires T cell

1. opsonin
2. macrophage
3. lysosome

Other

• Sweets causes coughs
• Parasites and iron causes lack of brain function
• Type O is an abence
• Histiocytes transport of cell
• Intact skin is the first
• Shorter peptide means cells are more complexed

Test your knowledge of immunology with these practice questions. Topics include antibody structure, protein electrophoresis, allergic reactions, complement activation, and diagnostic tests for autoimmune diseases. Review key concepts in immune responses.