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functional antigen 284 fungi
Dr. H. Hugh Fudenberg.
multivalent reactivity may enhance the affinity of multiple
antigen–antibody reactions. Avidity has a similar connotation,
but it is a less precise term.
functional antigen
Refer to protective antigen.
functional immunity
Refer to protective immunity.
fungal immunity
Nonspecific immune mechanisms of a host that form a
first line of defense against fungal infections include the
mechanical barriers provided by the skin and mucous membranes,
competition by normal bacterial flora for nutrients,
and the respiratory tract’s mucociliary clearance mechanism.
Fungi are not lysed by the terminal components of the
complement system and specific antibody, but complement
components serving as opsonins facilitate phagocytosis of
fungi by phagocytic cells. Fungi are powerful activators of
the alternative complement system. Neutrophils are very
significant in protection against various mycoses, including
disseminated candidiasis and invasive aspergillosis.
1. Chimeric
antibody
Human constant
2. Reshaped humanized
antibody with specificity
of original rodent antibody.
Rodent
hypervariable
Human constant
Rodent
variable
Human
framework
3. Antibody-toxin/enzyme
chimeric molecule
F(ab´) 2
Fc replaced by
enzyme or toxin
V
4.
Single domain antibody
5. Single-chain Fv molecule
created by linked V domains
from an L and an H chain
V H V L
Monocytes and resident macrophages vary in their ability
to kill fungi. Few specific antifungal activities of activated
human macrophages have been demonstrated.
Bronchoalveolar macrophages play an important role in the
immune response to inhaled fungi. Natural killer (NK) cells
inhibit the growth of C. neoformans and P. brasiliensis in
vitro. NK cells have also been shown to clear cryptococcus
from mice. Specific antibodies are of little use in host
defense against most mycoses, but specific cell-mediated
immunity is paramount for a protective immune response
to C. neoformans disease and dimorphic fungi. It is also
important for protection against dermatophyte infections.
Cell-mediated immunity plays an important role in protection
against mucocutaneous candidiasis. AIDS patients have
a high incidence of fungal infections. Cytokines formed
in a specific cell-mediated immune response facilitate the
antifungal action of NK cells, nonspecific T lymphocytes,
and neutrophils. Cytokines such as tumor necrosis factor
(TNF), granulocyte–macrophage colony-stimulating factor
(GM-CSF), and interleukin-12 (IL12) released during a
cell-mediated immune response may activate effector cells
to kill fungi. Immunosuppressive cytokines such as IL10
and transforming growth factor β (TGF-β) are also formed
in response to fungal infection. Severe fungal infections
usually occur in profoundly immunosuppressed patients
who have diminished responses to immunization. Defects
in host immunity associated with fungal infections are
being identified in order that cytokines such as interferon-γ
(IFN-γ) may be administered to chronic granulomatous
disease patients and GM-CSF may be administered to neutropenic
patients. Monoclonal antibodies against capsular
glucuronoxylomannan have been given to patients with
cryptococcosis.
fungi
Single-celled and multicellular eukaryotic microorganisms
such as yeast and molds. They readily invade and colonize
a host with compromised immunity, producing a variety of
diseases. Immunity to fungi involves both cell-mediated
and humoral immune responses.
Linker peptide
Genetically engineered antibodies.
6. Bi-specific antibody created
by protein engineering
Heavy chain
Light chain
7. Bi-specific antibodies created
by protein engineering
Specificity
B
Specificity A
Specificity B
Specificity
A