MICROPARA | Host Response to Infection

IMMUNOLOGY

study of the immune system & the immune response

IMMUNOGEN

any substance that is capable of inducing immune response, whether humoral, cellular or both.

ANTIGEN

a substance that is recognized by a particular antibody (Ab) or T cells &serves as the target of the immune response

IMMUNITY

aka as RESISTANCE; the ability to guard against disease caused by microbes, their products including pollution, toxins, and animal dander.

SUSCEPTIBILITY

lack of immunity

INNATE & ADAPTIVE

two types of immunity in general

INNATE IMMUNITY

refers to all body defenses that protect the body against any kind of pathogen.

ADAPTIVE IMMUNITY

refers to defenses (antibodies) against specific microorganisms.

INNATE IMMUNITY

- aka NATURAL IMMUNITY.

- exist from the time we are born, prior to exposure to antigen.

FIRST LINE OF DEFENSE

- skin, mucous membrane

- includes the intact skin,

- enzymes in tears in body secretions,

- normal flora

SECOND LINE DEFENSES

non-specific host barriers

- natural killer cells, phagocytes, inflammation, fever, and antimicrobial substances

- innate arm of immune system

INTERFERONS

a substance released by activated cells and inhibit viral replication

THIRD LINE OF DEFENSE

- ADAPTIVE arm of immune system

- B cells and T cells

ADAPTIVE IMMUNITY

aka ACQUIRED IMMUNITY

- occurs AFTER exposure to antigen, improves upon repeated exposure

- antigen specific and is systematic

ANTIGEN SPECIFIC

- recognizes and acts against particular foreign substances

SYSTEMIC

-immunity is not restricted to the initial infection site

ADAPTIVE IMMUNITY

- responsible for conferring lifetime protective immunity to re- infection with same pathogen.

ADAPTIVE IMMUNITY

There is a Memory that recognizes and mounts a stronger attack on previously encountered pathogens

HUMORAL AND CELLULAR IMMUNITY

two arms of adaptive defense system

HUMORAL IMMUNITY

- antibody-mediated immunity.

- provided by antibodies present in body fluid

HUMORAL IMMUNITY

- primarily involves B cells and

- neutralizes threats outside human cells.

CELLULAR IMMUNITY

- cell-mediated immunity.

- living cells target virus-infected cells, cancer cells, and cells of foreign grafts

CELLULAR IMMUNITY

- primarily involves T cells and deals with threats INSIDE cells

ACTIVE & PASSIVE IMMUNITY

two types of adaptive immunity

ACTIVE ACQUIRED IMMUNITY

acquired as a result of the active production of antibodies

PASSIVE ACQUIRED IMMUNITY

acquired as a result of receipt of antibodies produced by another person or by an animal.

LYMPHOCYTES

cells that circulate in your blood that are part of the immune system

THE IMMUNE SYSTEM

to defend the host against infection

B LYMPHOCYTES/ B CELLS,

T LYMPHOCYTES/T CELLS

cells involved in the immune system

THYMUS & BONE MARROW

primary (central) lymphoid organs

BONE MARROW

where B & T originates

B CELLS

remain in bone marrow to reach maturity

T CELLS

need to migrate in the thymus where they mature

SECONDARY (PERIPHERAL LYMPHOIDS ORGANS)

- LN, Spleen, Mucosa-Associated Lymphoid Tissue

- sites where antigens from organisms entering body or present onbodysurfacearetrapped

B LYMPHOCYETS (B CELLS)

- differentiate into antibody producing plasma cells.

- produces antibodies.

- Antigen presenting cell.

- Possesses immunologic memory

- with Ig on its surface (IgM & IgD)

T helper cells (CD4+ T cells)

& Cytotoxic T cells (CD8T cells)

two main subsets of T CELLS

T helper cells (CD4+ T cells)

promote inflammation & antibody production

Cytotoxic T cells (CD8T cells)-

Recognize & kill virus infected cells, tumor cells & foreign cells also possess immunologic memory

ANTIBODIES

are globulin proteins (immunoglobulins) that react w/ specific antigen that stimulated their production.

IgG

IgA

IgM

IgE

IgD

5 MAIN CLASSES OF ANTIBODIES

IgG

- predominant antibody in secondary response & major defense against bacteria & viruses

IgG

MOST ABUNDANT ANTIBODY IN THE NEWBORNS

IgG

MAIN immunoglobulin

IgA

- main Ig in secretions

- Prevents attachment of organisms (bacteria & viruses) in mucous membranes

IgA

is found in high concentrations in the mucous membranes

IgM

- LARGEST & MAIN immunoglobulin (Ig)

- produced early in primary response.

IgM

found mainly in the blood and lymph fluid

IgE

- mediates immediate (anaphylactic) hypersensitivity reactions

IgE

Provides defense against certain parasites

IgE

- Binds on surface of mast cells & basophils.

- Serves as Ag receptor for Ag(allergen)

IgD

- no known Ab function .

- Found on surface on many B cells, serves as marker for B cells

IgD

exist in small amounts in blood and is the least understood antibody

PRIMARY RESPONSE

- Involved during 1st encounter with Ag.

- Ab become detectable in serum after a period of 7-10 days, but can be longer depending on nature & dose of Ag & route of administration. First to appear are IgM followed by Ig IgG or IgA

SECONDARY RESPOSNE

Occurs after re-exposure to same Ag

CELL-MEDIATED IMMUNITY (CMI)

- imparts resistance & aids in recovery

MACROPHAGES, HELPER T CELLS, NK CELLS, CYTOTOXIC T CELLS

components of CMI

MACROPHAGES

—present the Ag to T cells, ingest & destroy microbes

HELPER T CELLS

participate in Ag recognition & in regulation of B cells & cytotoxic T cells fxns

NK CELLS

can inactivate pathogens

CYTOTOXIC T CELLS

can kill virus-infected cells with or without antibody( Ab).

MAROPHAGES & HELPER T CELLS

cells produces substances called cytokines w/ can activate further helper T cells & cytotoxic T cells

HYPERSENSITIVITY

used when an immune response results in an exaggerated or inappropriate reactions that are harmful to the host

Type I- Immediate Anaphylactic Hypersensitivity, Type II- Cytotoxic/Cytolytic Hypersensitivity, Type III- Immune Complex Hypersensitivity, Type IV- Delayed (cell- mediated) Hypersensitivity

4 Main TYPES OF HYPERSENSITIVITY REACTIONS

Type I- Immediate Anaphylactic Hypersensitivity

allergy (pollens, animal fur, food various drugs)

Type II- Cytotoxic/Cytolytic Hypersensitivity

- Ab dependent cellular cytotoxicity (ADCC)

- . Ab complement dependent lysis-

- Formation of antibodies Ab directed against receptors.

Type III- Immune Complex Hypersensitivity

Occurs when Ag- Ab complexes activate complement & induce an inflammatory reaction in tissues

- malaria, dengue, hepa b infections

Type IV- Delayed (cell- mediated) Hypersensitivity

- Involves T lymphocytes, not Ab.

- The response is delayed in that it starts hours or days after contact with the Ag & often lasts for days. Involves either helper T cells or cytotoxic T cells.

VACCINE

a substance that is used for the production of antidotes in the body and provides immunity against one or a few diseases

VACCINE

a biological and formulated preparation to provide acquired immunity for a particular disease

VACCINE

an agent which contains a weakened or killed form of the disease-causing agent, its surface, or its toxins.

VACCINATION

process of implementing the vaccine is called

VACCINATION

responsible for the clearance of many diseases, especially infectious diseases like smallpox and chickenpox

"from the cows"

vaccine is derived from the word, "vaccines" which means?

EDWARD JENNER

first official vaccination was developed by?

EDWARD JENNER

founder of vaccinology

1798

very first small pox was developed.

Live Attenuated Vaccines:

passing the disease-causing virus through a series of cell cultures or animal embryos

Inactivated Vaccine

are developed by inactivating a pathogen, typically using chemicals or even heat such as formaldehyde or formalin

Toxoid Vaccine

immunization of pathogens can be developed by inactivating the toxin that causes disease symptoms

Subunit Vaccine

- only used as part of a target pathogen to promote a response from the immune system.

- This can be done by isolating a specific protein from a pathogen and presenting it as an antigen on its own

. Conjugate Vaccine

somehow similar to recombinant vaccines, they are made up of a combination of two different components.

Valence Vaccine

- Vaccines may be monovalent.

- made to immunize against twoor more viruses of the same microorganism

Heterotypic Vaccine

"jennerian vaccines"

- are pathogens of different animals that either do not cause disease or cause disease or cause mild disease in the organism being treated

mRNA Vaccine

s a different type of vaccine which is a combination of nucleic acid RNA, packaged within a vector such as lipid nanoparticles