How do pathogens often enter the blood stream?
Teeth brushing
Local infections
Wounds
Medical procedures
What are the two functions of the spleen?
- ) Secondary lymph organ (white pulp)
2. ) Filter for the blood (red pulp)
What needs to be done to some microbes in order for them to be phagocytized?
They must be opsonized by antibodies (encapsulated bacteria)
What are patients with a splenectomy or asplenia susceptible to?
Encapsulated bacteria
What must patients with splenectomies do before dental work or surgeries?
Take prophylactic antibiotics
What is a splenectomy considered an example of?
Acquired (secondary) immunodeficiency
What antibody is found in the mucosa of the upper respiratory tract?
Secretory IgA (transcytosed across epithelial cells)
Three general defense in upper airway:
Lumenal
Epithelial
Blood-derived cells of mucosa
What is the most abundant antibody in the alveoli?
IgG1-3
Which IgG antibodies opsonize?
IgG1
IgG3
What complement opsonizes?
C3b
What protein in lower respiratory tract also opsonizes?
C-reactive protein
What is the first line of defense in lower airways?
Alveolar macrophages
What is the major defender against bacterial pathogens in lower respiratory tract?
Neutrophils
Border between upper and lower respiratory tract:
Upper: nose-larynx (glottis vocal cords)
Lower: larynx-alveoli
What are two options for alveolar macrophages once they come in contact with pathogens?
Neutralize and kill
Regulate lung inflammation
What cytokines do alveolar macrophages release to mediate inflammation?
IL-1alpha
IL-1beta
TNF-alpha
What does release of alveolar macrophage cytokines initiate?
Inflammation and neutrophils to come to the side
What do neutrophils generate?
Neutrophil net to made of chromatin with anti-microbial proteins
What do CD4+ T cells do?
Helper T cells to activate B cells
What do CD8+ cells do?
Kill infected cells and activate macrophages
How do CD4+ cells activate macrophages?
Binding CD40 ligand with cytokine coreceptor
What does BALT stand for?
Bronchus-Associated Lymphoid Tissue
What is BALT?
Specialized epithelial cells that microbes and antigens can pass through (endocytosis or phagocytosis)
Where is BALT found?
Bifurcation of the bronchus; more prevalent after infections
