1. IMMUNOLOGY & ONCOLOGY
EMERITA C. MENDOZA, R.N., M.D.

2. Immune System The body’s special defense against foreign organisms
Includes: lymphoid organs (lymph nodes, spleen, & thymus gland) and their products (lymphocytes & antibodies) and macrophages (phagocytes found in the blood, brain, liver, lymph nodes, & spleen)

3. Defense Mechanisms Specific Nonspecific T Lymphocytes Inflammation
B lymphocytes
Cell-mediated Immunity
Antibody-mediated Immunity
Nonspecific
Inflammation
Phagocytosis
Interferons

4. Inflammation
a response of body tissues to injury or irritation; characterized by pain and swelling and redness and heat

5. Phagocytosis
One of the main functions of inflammation is to bring large numbers of phagocytes to the affected area.
Once there, phagocytes ingest bacteria by flowing around them and engulfing them; this is phagocytosis.
As a bacterium is ingested, it is neatly packaged within a vacuole formed by membrane pinched off from the cell membrane.
One or more lysosomes adhere to the vacuole and release enzymes into it that kill the bacterium.

6. Interferons
When infected by viruses or other intracellular parasites (some types of bacteria, fungi, and protozoa], certain types of cells respond by secreting proteins called interferons.
These proteins trigger other cells to produce antiviral proteins. Viruses produced in cells exposed to interferon are not effective at infecting new cells.

7. 2 Major Disease Fighters of the Immune System
T-cell lymphocytes 
differentiate primarily in the thymus and are central to the control and development of immune responses.
B-cell lymphocytes 
immune system cells released from the bone marrow, which produce antibodies.

8. T-cell lymphocytes Involved in cell-mediated immunity
Originate from bone marrow stem cells & are processed in the thymus gland
When an Ag is encountered, the T-cell multiplies rapidly to produce cells that destroy the Ag

9. T Cell Lymphocytes
Attach to Ag & directly destroy them (cytotoxic T-cell or T8 cells)
Secrete proteins (cytokines: interferons & interleukins) that help other cells respond to Ag
Act as helper cells (T4 cells) to promote antibody synthesis by B cells and stimulate T cells.
Act as suppressor cells to inhibit B and T cells.

10. B-cell lymphocytes Involved in humoral immunity (Ab-mediated)
Originate from bone marrow stem cells
When confronted with a specific type of Ag, B-cells transform into plasma cells  produce antibodies called immunoglobulins:
IgA – mainly found in secretions
IgG – most abundant, crosses the placenta to provide immunity to newborn
IgE – important in allergic reaction & parasitic infection
IgM – produced in the primary response to Ag
IgD – no known antibody function

11. Cell-mediated Immunity -bind to the surface of other cells that display the antigen and trigger a response. The response may involve other lymphocytes and leukocytes.
Antibody-mediated Immunity -Antibodies, dissolved in blood, lymph and other body fluids bind the antigen and trigger a response to it.

12. Immunity
the body’s ability to resist foreign organisms and toxins (poisons) that damage tissues & organs
2 types:
Natural immunity - nonspecific
Acquired immunity - specific
Acquired active immunity
Acquired passive immunity

13. Graft Rejection It is an immune response aimed at transplanted tissues
Due to incompatibility of histocompatibility genes and antigens
1/1 match in autografting & between identical twins
¼ match in siblings
1/1000 match in unrelated persons
Prevention: use of drugs & xrays to kill T-lymphocytes (side effect: suppress immune system)

14. Hypersensitivity
an allergy; an exaggerated or inappropriate immune response categorized based on which part of the immune system that is involved and the onset of response

15. ONCOLOGY
The science dealing with the physical, chemical and biological properties and features of cancer, including the causes and progression of the disease. Doctors who specialize in oncology are called oncologists.

16. Introduction to ONCOLOGY
Cancer (CA) – a disease characterized by unrestrained & excessive growth of cells in the body
CA cells compress, invade, & ultimately destroy surrounding normal tissue
may have local & metastatic growth
in females: lung CA, breast & colorectal CA
in males: lung, colorectal, & prostate CA

17. Carcinogenesis Theory of Immunosurveillance
failure of the immune system to eradicate abnormal cells
Malignant transformation resulting from damage to the genetic material, or DNA, of the cell
the processes of mitosis and protein synthesis are disturbed
altered DNA & altered cellular programs make new signals that lead to movement of cells, invasion of adjacent tissue, and metastasis
changes established in a CA cell is passed on to daughter cells  mutation
normal cells undergo apoptosis (spontaneous disintegration); CA cells do not, live indefinitely

18. Environmental Agents or carcinogens
Chemical carcinogens:
hydrocarbons in cigarettes, cigars, pipe smoke, & auto exhaust
insecticides, dyes, industrial chemicals, insulation
hormone: Diethylstilbestrol (DES) – synthetic oestrogen prescribed in the 1950s, 1960s, and early 1970s to women to prevent miscarriage causes malignant tumor CA of the vagina
drugs: estrogen – causes CA by stimulating proliferation of cells in target organs such as uterine lining

19. Radiation: wave of energy
sunlight, x-rays, radioactive substances, nuclear fission
leukemia – occupational hazard of radiologists
Hiroshima & Nagasaki atomic bomb survivors
ultraviolet radiation in sunlight – especially for Caucasians or fair-skinned individuals

20. Viruses: Oncogenic viruses
caused by RNA viruses (aka retroviruses) & DNA viruses
Human T-Lymphocytic Virus (HTLV) – leukemia in adults
Human Immune Deficiency Virus (HIV) – Kaposi sarcoma associated with AIDS
Papilloma virus – cervical CA
Epstein Barr Virus (EBV) – Burkitt lymphoma

21. Oncogene or CA causing gene
a piece of DNA whose activation is associated with the conversion of a normal cell into a cancerous cell
ras oncogene– colon cancer
myc – lymphoma
bcr-abl – chronic myelogenous leukemia

22. Heredity
Susceptibility to some CA forms is transmitted from parents to offspring through defects in the DNA of the egg & sperm cells
tumors arise because of inherited or acquired abnormalities in suppressor genes (regulate growth, promote differentiation, & suppress oncogenes from causing cancer)
ex.: retinoblastoma, polyposis coli syndrome, & certain forms of colon, breast, & kidney CA
genetic screening – to determine presence of cancer-causing gene