Immune Regulation (RVSP) Flashcards
What are the mechanisms of immunoenhancement/immunopotentiation?
- increasing the rate at which the response occurs
- elevating its magnitude
- ncreasing the duration of the response
The augmentation of immune responsiveness by immunization or other means
Immunoenhancement/Immunopotentiation
Example of a nonspecific potentiator
Adjuvants
Substances that enhance the immunogenicity of molecules without altering their chemical composition
Adjuvants
3 ways an adjuvant enhances the immunogenicity of molecules
- increase the efficiency of the macrophage processing of Ag
- prolonging the exposure to an Ag
- amplifying the proliferation of immunocompetent lymphocyte by enhancing lymphokine activity
Classic adjuvant used in experimental animals
Freund’s adjuvant
Emulsifying agent of Freund’s adjuvant
Paraffin or mineral oil
2 types of Freund’s adjuvant
- Incomplete Freund’s adjuvant (IFA)
- Complete Freund’s adjuvant
Class of IFA
Water in oil with antigen
IFA increases _________ response about _________
Humoral Ab
100 fold
The IFA prolongs the phase of active Ig synthesis by ________
Months
What is in the Complete Freund’s adjuvant that is not present in IFA?
Mycobacterial cell wall components
The complete Freund’s adjuvant markedly increases ___ and ___
Humoral immunity
Cell-mediated immunity
3 types of specific potentiators
Helper factors
Immunogenic RNA
Transfer factors
HIT
Specific potentiator; secreted by T cells ff interaction of Ag specific receptor with its homologous epitope
Helper factors
Specific potentiator; an Ag specific dialyzable extract of immune T cells that is capable of transferring CMI
Transfer factors
Specific potentiator; extracted from lymphoid tissues following Ag injection
Immunogenic RNA
Specific potentiator; an Ag receptor complexed with cellular RNA which greatly increases immunogenicity of a molecule
Immunogenic RNA
Reduction in a large portion of immune responsiveness
Immunosupression
3 types of immunosupression
Physical means
Chemical and Biologic means
Immunosupression associated with diseases
2 physical means of immunosupression
Surgical manipulation
Ionizing radiation
Effect of surgical manipulation of bursa of Fabricius/thymus during neonatal period
Immunologic competence not developed in the corresponding cell line
Effect of surgical manipulation of bursa of Fabricius/thymus after immunologic development
Very little effect on immunologic competence
Peripheral lymphoid tissues removed in surgical mannipulation
Lymph nodes
Lymphoid cells
Organs damaged by ionizing radiation
Lymphoid organs
Bone marrow
3 chemical and biologic means of immunosupression
Lymphocytic agents
Lymphocytotoxic agents
Antibodies
Can track the expression of the immune response but more effective in disrupting the initian of the immune response
Lymphocytic agents
4 types of lymphocytotoxic agents
Antimetabolites
Alkylating agents
Antibiotics
Cortisone
Lymphocytotoxic agent; interferes with DNA synthesis
Antimetabolites
Examples of antimetabolites
Purine and pyrimidine
Analogues
Folic acid antagonists
Lymphocytotoxic agent; interferes with cell division by altering guanine so DNA base pairing errors occur
Alkylating agents
Lymphocytotoxic agent; can crosslink DNA strands thus blocking replication
Alkylating agents
Example of alkylating agent
Cyclophosphamide
Lymphocytotoxic agent; supresses graft rejection reactions
Antibiotics
Lymphocytotoxic agent; exerts an inhibitory effect on IL-2 action thus blocking the expansion of the helper/inducer T cell population
Antibiotics
Example of antibiotics
Cyclosporin
Lymphocytotoxic agent; immunosupressive & anti-inflammatory
Cortisone
Lymphocytotoxic agent; lymphocytic to animals, not in humans; alters cell migration & causes lymphopenia & monocytopenia shortly after injection
Cortisone
Abs that induce immune deficiency in transplant patients by supression of CMI
Abs that react with lymphoid cells particularly thymocytes
Ab that blocks host IR
Preformed Abs followed by injection of specific Ag
Abs that specifically abort a specific response
Abs specific for the Ag combining site
2 congenital immunodeficiencies
Bruton’s agammaglobulinemia
DiGeorge syndrome
Lymphocytes that fail to develop in Bruton’s agammaglobulinemia
B cells
Recurrent infection in Bruton’s agammaglobulinemia
Bacterial infections
What is the problem in DiGeorge sydrome?
Failure of the development of third and fourth pharyngeal pouches during embryogenesis
Recurren infections in DiGeorge syndrome
Recurrent viral disease
A malignancy that dirupts normal lymphocyte functions directly or may ‘crowd out’ normal lymphocytes from bone marrow & peripheral lymphoid tissues
Lymphomas
Infection that causes a transient depression of CMI
Measles
Infection that causes a profound immunosupression which renders the host susceptible to fatal infection from opportunistic pathogens
HIV
Immunity that is most sensitive to nutritional deprivation
CMI
Other components of immunity that are affected by malnutrition other than CMI
Humoral immunity
Complement
Phagocyte functions
Immunosupression associated with diseases
Congenital immunodeficiencies
Malignancies
Infections
Malnutrition
Absence of specific immune response in a fully competent person
Tolerance
2 types of tolerance
- Naturally acquired (autolerance, neonatal, natural tolerance)
- Immune tolerance
Escape from naturally acquired tolerance leads to
Autoimmune diseases
When is the ability to recognize one’s own tissues acquired?
During fetal development
Theory related to naturally acquired tolerance
Clonal deletion theory
2 gradations of tolerance
Partial
Immune deviation/split tolerance
Gradation of tolerance; unable to respond to some of the epitopes on the Ag but can respond to others
Partial
Gradation of tolerance; one of the immune responses can be interferred with, but not another
Immune deviation/split tolerance
4 pathways to B cell tolerance
Functional deletion
Antibody forming cell blockade
Cisnal abortion
Clonal exhaustion
3 factors that determine the type of B cell tolerance
Maturity of the cell
Ag
Manner of Ag presentation
Pathway to B cell tolerance; low conc of multivalent Ag may cause the immature clone to abort
Cisnal abortion
Pathway to B cell tolerance; repeated antigenic challenge with T independent Ag may remove all mature B cell clones
Clonal exhaustion
Pathway to B cell tolerance; absence of T helper cell with presence of T dependent Ag or an excess of T independent Ag prevents mature B cell from functioning properly
Functional deletion
Pathway to B cell tolerance; high conc of T dependent Ag are blocking the receptors of the cells hereby interferring Ab secretions
Antibody forming cell blockade
3 pathways to T cell tolerance
Clonal abortion
Functional deletion
T supression
Pathway to T cell tolerance; immature T cell clones may be aborted in a similar manner to B cell
Clonal abortion
Pathway to T cell tolerance; subsets of mature T cells may be individually deleted leading to the loss of only one of the functions of the T cell group
Functional deletion
Pathway to T cell tolerance; supressor T cells actively supress the actions of the T cell subsets or B cells
T supression