B lymphocytes - 2026 ACF Regionals

Question

Pax5 transcription factors play a major role in the differentiation of these cells by promoting the expression of their co-receptor CD19. For 10 points each:

[10e] Name these cells deficient in X-linked agammaglobulinemia, resulting in patients producing little antibodies. These cells mature in bone marrow in contrast to another class of immune cells that mature in the thymus.

ANSWER: B lymphocytes [or B cells; accept pro-B cells or pre-B cells; accept plasma cells]

[10m] One of these enzymes, first identified by Ogden Bruton, is defective in XLA. After cytokine receptors dimerize, the Janus type of these enzymes transphosphorylates each other at a certain amino acid residue.

ANSWER: tyrosine kinases [or TKs; accept Bruton’s tyrosine kinases or BTKs; accept Janus tyrosine kinases; accept receptor tyrosine kinases or RTKs; accept non-receptor tyrosine kinases or NRTKs; prompt on kinases; prompt on JAKs or JAK-STAT signaling]

[10h] During negative selection, self-reactive B cells can enter this state of unresponsiveness to any stimulatory signal. In the absence of co-stimulatory CD28, T cells enter this state via a calcium-dependent NFAT pathway.

ANSWER: anergy [accept clonal anergy; accept anergic state; reject “dormancy”]

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Summary


California (North)	Main Site	Y	3	16.67	100%	67%	0%
Canada	Main Site	Y	1	10.00	100%	0%	0%
Florida	Main Site	Y	3	6.67	33%	0%	33%
Lower Mid-Atlantic	Main Site	Y	9	5.56	44%	11%	0%
Midwest	Main Site	Y	9	11.11	56%	33%	22%
Northeast	Main Site	Y	6	16.67	83%	50%	33%
Overflow	Main Site	Y	4	12.50	75%	50%	0%
South Central	Main Site	Y	2	10.00	100%	0%	0%
Southeast	Main Site	Y	7	11.43	71%	43%	0%
UK	Main Site	Y	6	8.33	50%	17%	17%
Upper Mid-Atlantic	Main Site	Y	9	11.11	89%	22%	0%
Upstate NY	Main Site	Y	4	7.50	75%	0%	0%

Data


Berkeley A	Berkeley D	10	10	0	20
Stanford B	Berkeley B	10	0	0	10
Stanford A	Berkeley C	10	10	0	20
McGill A	UBC B	10	0	0	10
Central Florida C	Central Florida B	0	0	0	0
Florida B	Florida A	0	0	0	0
Central Florida A	Florida C	10	0	10	20
Duke	William and Mary	10	0	0	10
James Madison A	Liberty C	0	0	0	0
Liberty A	South Carolina A	0	0	0	0
James Madison B	Liberty B	0	0	0	0
NC State B	North Carolina B	0	0	0	0
North Carolina C	NC State A	10	0	0	10
South Carolina B	VCU	0	0	0	0
North Carolina A	Virginia Tech A	10	10	0	20
Virginia Tech B	Virginia	10	0	0	10
Notre Dame A	Chicago B	10	10	10	30
Illinois B	Chicago C	0	0	0	0
Purdue B	Chicago D	0	0	0	0
Notre Dame B	Chicago E	0	0	0	0
Indiana A	Illinois A	10	0	0	10
Northwestern B	Illinois C	10	0	0	10
Indiana B	Northwestern D	0	0	0	0
Northwestern C	Indiana C	10	10	0	20
Purdue A	Chicago A	10	10	10	30
Brandeis B	Bowdoin A	10	0	0	10
MIT	Brandeis A	10	10	10	30
Harvard A	Dartmouth A	10	10	0	20
Southern Connecticut State	Dartmouth B	0	0	0	0
Yale	Harvard B	10	0	0	10
Brown	Bowdoin B	10	10	10	30
Georgia Tech A	Minnesota A	10	10	0	20
Carleton College	Washington B	0	0	0	0
Claremont	Iowa State	10	0	0	10
Texas A	Murray State A	10	0	0	10
Texas B	Texas A&M A	10	0	0	10
Alabama A	Tennessee B	0	0	0	0
Bruin	WashU B	10	0	0	10
Georgia Tech D	Louisville A	10	10	0	20
Kentucky	Louisville B	10	10	0	20
Mississipi State	Georgia Tech B	0	0	0	0
Tennessee A	Sewanee	10	0	0	10
WashU A	Vanderbilt B	10	10	0	20
Missouri A	Washington A	10	10	0	20
LSE	Bristol	0	0	0	0
Cambridge B	Imperial A	10	10	10	30
Oxford A	Cambridge C	10	0	0	10
Durham	City St. George's	0	0	0	0
Edinburgh B	Imperial C	10	0	0	10
UCL	Oxford B	0	0	0	0
Maryland A	Columbia A	10	10	0	20
John Jay	Catholic	10	0	0	10
Johns Hopkins A	NYU B	10	0	0	10
NYU C	Johns Hopkins B	10	0	0	10
Rutgers A	Rutgers B	10	0	0	10
Swarthmore	Maryland C	0	0	0	0
Georgetown	Columbia C	10	0	0	10
Maryland B	Vassar	10	10	0	20
Cornell C	Binghamton A	10	0	0	10
Rochester	Binghamton B	0	0	0	0
Cornell A	Penn State	10	0	0	10
Cornell B	RIT	10	0	0	10
NYU A	Columbia B	10	0	0	10