Week 1
If you add 1 mL of a solute into 9 mL of a solvent, what ratio of dilution would this be?
This would be a 1:10 dilution scheme. This is because we are adding 1 mL into 9 mL, making the "whole" part of the dilution 9 + 1 = 10 mL.
What concentration of ethanol should be used during aseptic technique?
70 % ethanol; this is effective enough to kill most unwanted microbes, but not so strong that it would damage the cells.
This type of receptor activates the NF-κB pathway downstream, leading to the production of pro-inflammatory cytokines.
a) TLR4
b) Fc
c) both
a) TLR4; Fc receptor binding triggers phagocytosis. The membrane of the phagocyte extends around the target, enveloping it, and pinching off into a discrete phagosome.
The ______ chamber is a migration assay designed to measure cell migration that consists of two fluid‐containing chambers separated by a microporous membrane.
What is the Boyden chamber?
What does ELISA stand for?
Enzyme-Linked Immunosorbent Assay
True or False: When using a pipette, one should never change the tip between samples as this could cause different volumes to be dispensed due to micro-differences within each pipette tip.
False: One should ALWAYS change the pipette tip between samples as this will decrease experimental errors caused by contamination.
What is the main reason immunologists passage cells?
To give the cells enough room to grow/proliferate and replenish nutrients.
Which type of polarization is activated by particular cytokines, such as IL-4, IL-10, MCSF, etc.?
M2 polarization is activated by particular cytokines and initiates wound healing responses such as inducing collagen production, contribute to tissue repair, and can promote tumor cell proliferation.
M1 polarization is classically activated via LPS and initiates immune responses such as the release of pro-inflammatory cytokines, phagocytosis, and nitric oxide production.
Neutrophil directional migration in response to chemical gradients is called _________.
What is chemotaxis?
How many antibodies are used when performing an indirect sandwich ELISA?
1/10 x 10^-2 x 10^-4 x 1/10^2 = ?
a) 1.0 x 10^12
b) 1.0 x 10^-7
c) 1.0 x 10^-9
c) 1.0 x 10^-9
The correct answer is c) because when multiplying exponential powers, we can simply add together the exponents. Since, 1/10 = 10^-1 and 1/10^2 = 10^-2, the answer will be -1 + -2 + -4 + -2 = 1.0 x 10^-9.
True or False: Trypan blue is only capable of staining live cells.
False: Trypan blue is only capable of staining DEAD cells; this is because the cell membrane is permeable since the cells is no longer alive.
What is the main reason immunologists fix cells during phagocytosis?
Fixation stops the reaction and preserves the integrity of cellular components for observation.
What is the function of fMLP?
fMLP is a synthetic peptide that resembles tissue bacteria. It is a potent mediator of neutrophil chemotaxis.
___ is the detection reagent used in the indirect sandwich ELISA whereas the ___ substrate was used to detect it.
What is HRP and TMB?
You have a solution of 3 mL neutrophils at 3x10^6 cells/mL. You add 12 mL of media to the cells. What is the final concentration in cells/mL?
Step 1: Identify what you have and what you are looking for. Have: V1=3 mL, C1=3x10^6 cells/mL, V2=12+3=15 mL. Looking for: C2=?
Step 2: Set up the equation. C1V1=C2V2; (3x10^6 cells/mL)(3 mL)=C2(15 mL).
Step 3: Solve.(9.0x10^6 cells)/(15 mL)=C2; 6.0x10^5 cells/mL=C2.
You dilute 100 ul of THP-1 cells in 400 ul of trypan blue and 500 ul of PBS. You use a hemocytometer to count your cells. The live cell counts from 5 squares are: 34, 38, 33, 47, 41. How many live cells were in your original solution in cells/mL?
3.86 x10^6 live cells in original solution;
1. (34 + 38 + 33 + 47 + 41) / 5 = 38.6 cells
2. 38.6 cells x 10^4 = 3.86 x 10^5 cells
3. 100 µL : 400 + 500 = 900 µL → 100:1000 → 1:10 → 10 x 3.86 x 10^5 cells
What is the first step of phagocytosis?
Recognition of a foreign molecule
What are the four stages in the process of chemotaxis?
1) rolling
2) integrin activation by chemokines
3) adhesion
4) migration through the endothelium
What were we testing for in the indirect sandwich ELISA experiment?
We were testing for the presence and relative concentration of the HIV antigen.
Which type of immune cell is responsible for engulfing and destroying pathogens and can be visually characterized by its kidney-shaped nucleus?
What is a neutrophil?
3.86 x10^6 live cells in original solution; 1.3 x 10^6 dead cells in original
What is the cell viability of the original solution?
(no. of live cells) / (no. of live + dead cells) x 100 = cell viability
(3.86 x 10^6 live cells) / (5.16 x 10^6 total cells) x 100 = 75.7 % viability
LPS activates macrophages by binding to this receptor on the surface of macrophages.
What is the Toll-like Receptor 4 (TLR4)?
The innate immune system recognizes the products of microbes, called __________ , or injured or dead host cells, called ___________ via pattern recognition receptors.
What are pathogen‐associated molecular patterns (PAMPs) and damage‐associated molecular patterns (DAMPs)?
What outcome would we expect for the most effective antiretroviral drug combination to have on a patient?
The drug combination that results in lower viral load in the patient is interpreted as a more effective treatment for HIV; this is because less antigen detection means less occurrence of viral replication.