Download Specific Resistance = Immunity

Specific Resistance =
Immunity
Lymphocytes (review)
Antigens & Antibodies
Acquired Immunity
Humoral Immunity: B-cell Function
Cell Mediated Immunity: T-cell Function
Stages of Disease Development
Lymphocyte
B cells:
Interact with antigens;
may develop a clonal
population of memory
cells or become
stimulated, divide and
mature into antibody
producing plasma cells.
Antibody functions are
called Humoral Immunity.
T cells:
Act
as either “helpers” in
communicating the
presence of an antigen;
or cytotoxic agents to
destroy infected cells.
These functions are
called Cell-Mediated
Immunity.
100 million produced per day
therefore others must die (apoptosis
= programmed cell death)
Antibody Monomer
Structure:
Immunoglobin (Ig) = antibody
Many possible antibodies
with different antigenic
binding sites due to variable
region diversity of long and
short chains.
Antigen-Antibody
Interaction
Antigen = a substance with unique 3D
form that causes antibody formation in
B cells (lymphocytes).
Antigens may possess one or more
types of reactive molecular
components; antigenic determinants or
epitopes.
Antigen binding sites on the antibody
Fab fragments specifically recognize
and chemcially interact with an epitope.
Because a single antibody recognizes a
single epitope, there may be multiple
antibodies generated against an antigen
with more than one epitope
Antigens can be
components of whole
microbes or viruses.
Antigens can be derived from very small molecules called
haptens, which without some carrier molecule or cell would not
elicit an immune response alone. This is the case for many drugs
and/or toxins (e.g. some venoms). Think of a heptan as
functioning as an incomplete antigen.
Antibody Classes
• IgG (80%; monomer; passive
to fetus/newborn);
• IgM (<10%, pentamer of IgG,
effective in agglutination); B cell
surface involved in activation.)
• IgA (< 15%; dimer; released
into fluid/mucus secretions);
• IgD (minor; monomer; on B
cell surface involved in
activation, blood and lymph).
• IgE (minor; monomer; on mast
cells and basophils; involved in
allergic response).
vaccine
antiserum
Passive = antibodies supplied to host from external sources, possibly prior to the
presence of any foreign antigen in the host.
Active = Foreign antigen introduced to host, which then stimulates immune response.