BIOL 2005 Lecture Notes - Cytolysis, Lipopolysaccharide, Interleukin 2

31 views4 pages

lilacplatypus913

30 Jan 2013

School

Department

Course

Professor

For unlimited access to Class Notes, a Class+ subscription is required.

Document Summary

Antigen recognition by t cells, i and ii: importance of t lymphocytes reconstitution expt) Both t and b cells are needed to generate an ab response (claman. Helper t cells activate b cells to produce ab. Cytotoxic t cells are the other type of t cell, which actively kill other cells. T cells are clonally selected via ag recognition by the t cell receptor. T cell ag recognition is similar (e. g. tcr, ig are homologous) to that in b cells, but distinct in mechanism. T cells develop in the thymus (this is the principle function of this organ) T cells recognize ag by a unique mechanism. T cells recognize linear 9-10 aa peptide sequences. T cells only recognize ag"s presented on the surfaces of other cells (apc"s such as dendritic cells or macrophages) Mhc restriction: the mhc allele expressed on the apc must be correct to pathogen response. Three types dp, dq, dr (in mouse i-a, i-e)

Related Questions

Fill in the blanks below, using words from the supplied word bank (case-sensitive). Not all words will be used, and some may be used more than once.

When the naive helper T cells are initially activated on a ________, most differentiate into wither TH1 ot TH2 effector cells, depending mainly on the ________ in their environment. TH1 cells activate ________, ________, ________, while TH2 cells activate mainly ________. In both cases, the effector helper T cells recognize the same complex of foreign peptide and _______ protein on the target cell surface as they initially recognized on the ________ that activated them. They activate their _______ by a combination of membrane-bound and secreted co-stimulatory proteins. One membrane signal protein used by TH1 and TH2 cells is _____ lignad.

dendritic cell nuclei target cells class II MHC

cytotoxic T cells basophils B cells CD40

signal proteins macrophages dendritic cell cancer cells

pucekangaroo923

Below is a paragraph describing HIV infection as they relate to the progress of infection. Please help choose the correct answer in each parentheses.

HIV initially infects (CD4+, or CD8+, or B) cells. These are helper T cells that activate (CD4+ or ,CD8+ or, B) cytotoxic T cells and (CD4+, or CD8+, or B) cells which produce antibodies. If HIV kills (CD4+, or CD8+) T cells then they cannot to do their job of activating these cells thus causing HIV infected people to be immunocompromised. Sometimes HIV infected people enter a latency period where the virus is inactive. This latency period can last for several years. During latency HIV (DNA, or RNA) becomes integrated into the (CD4+ or CD8+, or B) host cells genome and stops producing viral HIV RNA and new HIV virions. However, for some unknown reason, HIV comes out of dormancy and the viral (RNA, or DNA ) that was integrated in the (CD4+ , or CD8+,) T cell genome begins to transcribe more viral (DNA , or RNA) to make more viral (DNA, or RNA) using the host cells machinery. The viral (DNA, or RNA) then gets translated by host cell ribosomes to make viral proteins that eventually become packaged into new HIV virions. Consequently, after the latency period HIV becomes activated in the host cell. These cells present HIV antigen on their cell surface and alert (CD8+ or CD4+ or B) cells to kill them. As they are killed the infected (CD4+, or CD8+, or B) cells release the HIV virions into the blood stream to infect other (CD4+ or CD8+) cells such as macrophages and dendritic cells. This explains why after latency we see (CD4+, or CD8+) T cells continue to decrease while at the same time viral (DNA, or RNA) levels increase.

Based on your answers to the fill in paragraph, which statement is true?

A. Once active in CD8+ T cells, HIV can now replicate with impunity and infect other cells which explains the increase in HIV RNA after latency.

B. The increase in active HIV after latency accounts for why HIV can remain dormant for years after the initial infection.

C. CD4+ levels stabilize after the latency period and explain why there is little increase in HIV RNA levels.

D. Opportunist infections can occur after HIV latency because there are very few helper T cells to left to activate cytotoxic T cells and B cells to mount an immune response.

Question 4 (9 points):

To study T cell development, and self-restriction of T cells, you decide to perform some experiments. You obtain four mouse strains: B, B-MCC, K, and K-MCC. B strain mice express MHC molecules of the b haplotype (e.g. H-2K^b, H-2D^b, I-A^b) while K mice express MHC of the k haplotypes (e.g. H-2K^k, H-2D^k, I-A^k). The strains are otherwise genetically identical. B-MCC and K-MCC are identical to the B and K strains (respectively) excepts that contain a transgene encoding the antigen Moth Cytochrome which is not present in normal mice. MCC is produced as both a secreted and cytoplasmic protein and it is expressed by dendritic cells and thymic epithelial cells. You lethally irradiate groups of mice from all four strains and perform all possible bone marrow transfers among the mice. In other words, the BM of each strain is transplanted into mice of each strain, producing 16 different combinations of donor BM and recipient strain. You now take T cells from the lymph nodes of each of the 16 types of transplanted mice and test their ability to proliferate in response to MCC-presenting B cells that express only class II MHC molecule, I-A^k. Fill out the chart below by indicated which mice will have T cells that respond. Use (+) to indicated proliferation and NR to indicate a lack of proliferation. In addition, for the mice labelled a-e give a brief explanation for your answer. Include the mechanism of T cell selection experienced in thymus (positive selection, negative selection, or neglect) and the cells involved in selection (thymic epithelial cels, BM-derived APCs, or both).

Table (4 points, 0.25 points per box)

Recipient Strain Â®

BM Donor	B	B-MCC	K	K-MCC
B			c.
B-MCC			d.
K	a.	b.	e.
K-MCC

1 point for each explanation

yellowguinea-pig868

BIOL 2005 Lecture Notes - Cytolysis, Lipopolysaccharide, Interleukin 2

Document Summary

Get access

Related Documents

BIOL 2005 Lecture Notes - Leishmania, Natural Killer Cell, Gata3

BIOL 2005 Lecture Notes - Gata3, Interleukin 10, Immunoglobulin Class Switching

BIOL 2005 Lecture Notes - Cytokine, Interleukin 2, Cd24

Related Questions