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skb

07/02/06 - 08:46 AM       #1

MRl lpr/lpr mutant mie are useful biochemical research models because of their increased susceptibility to autoimmune disease. These mice are characterized by a defect in the fas gene and a marked increase in T-lymphocyte accumulation as compared with wild type animals. Based on these characteristics, which of the following is the most likely cause of the increased susceptibility of these mutants to autoimmune disease?

A. Decreased cell cycle transit time for activated T-lymphocytes
B. Decreased dependence on antigen presenting cells for T-lymphocyte activation
C. Decreased responsiveness to clonal deletion signals in the thymic cortex
D. Increased responsiveness to mature T-lymphocytes to antigenic stimulation
E. Increased thymocyte precursor proliferation in the bone marrow
F. Increased thymocyte proliferation rate in the thymic cortex

Cedrick
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07/02/06 - 01:22 PM       #2

raised eyebrow

raves
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07/06/06 - 10:39 AM       #3

C??

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alexaE
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07/06/06 - 10:45 AM       #4

C, since fas is implicated in apoptosis, including the apoptosis of T cells which respond to self antigens

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Cedrick
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07/06/06 - 10:47 AM       #5

I forgot about this one yes it is C.for sure



docarchana
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09/27/06 - 06:48 PM       #6

yes C is right

klimt
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10/01/06 - 08:25 AM       #7

C is correct

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smal
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10/16/06 - 03:40 PM       #8

YUPE THINK C

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ManuNastai

10/17/06 - 01:33 AM       #9

C defect in negative selection (induction of apoptosis in T cells that bind strong the "self"Class I MHC

yasmeen
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11/02/06 - 06:20 PM       #10

nodC









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