IgG subclass switch capacity is low in switched and in IgM-only, but high in IgD+IgM+, post-germinal center (CD27+) human B cells.

Recent studies have shown that in humans the germinal center reactions produce three types of V(D)J mutated B cells in similar proportions, i.e. Ig-switched, IgD-IgM+ (IgM-only) and IgD+IgM+ cells, and that together they form the CD27+ compartment of recirculating B cells. We investigated the Ig isotype switch capacity of these cells. Peripheral blood B subsets were sorted and IgG subclass secretion in presence or absence of IL-4 was compared in B cell assays which lead to Ig secretion in all (coculture with EL-4 thymoma cells) or only in CD27+ (CD40L stimulation) B cells. Already switched IgG+ B cells showed no significant sequential switch and IgM-only cells also had a low switch capacity, but IgD+CD27+ switched as much as IgD+CD27- B cells to all IgG subclasses. Thus, in switched B cells some alterations compromising further switch options occur frequently; IgM-only cells may result from aborted switch. However, IgD+CD27+ human B cells, extensively V(D)J mutated and "naive" regarding switch, build up a repertoire of B cells combining (1) novel cross-reactive specificities, (2) increased differentiation capacity (including after T-independent stimulation by Staphylococcus aureus Cowan I) and (3) the capacity to produce appropriate isotypes when they respond to novel pathogens.

Iowa's Center for Agriculture Safety and Health Annual Report, 2002

I-CASH is to enhance the health and safety of Iowa's agricultural community by establishing and coordinating prevention and education programs. This annual report gives information about a variety of areas that participate in I-CASH

Iowa's Center for Agriculture Safety and Health Annual Report, 2003

I-CASH is to enhance the health and safety of Iowa's agricultural community by establishing and coordinating prevention and education programs. This annual report gives information about a variety of areas that participate in I-CASH

Iowa's Center for Agriculture Safety and Health Annual Report, 2005

I-CASH is to enhance the health and safety of Iowa's agricultural community by establishing and coordinating prevention and education programs. This annual report gives information about a variety of areas that participate in I-CASH

Iowa's Center for Agriculture Safety and Health Annual Report, 2006

I-CASH is to enhance the health and safety of Iowa's agricultural community by establishing and coordinating prevention and education programs. This annual report gives information about a variety of areas that participate in I-CASH

Iowa's Center for Agriculture Safety and Health Annual Report, 2007

I-CASH is to enhance the health and safety of Iowa's agricultural community by establishing and coordinating prevention and education programs. This annual report gives information about a variety of areas that participate in I-CASH

Iowa's Center for Agriculture Safety and Health Annual Report, 2009

I-CASH is to enhance the health and safety of Iowa's agricultural community by establishing and coordinating prevention and education programs. This annual report gives information about a variety of areas that participate in I-CASH

Iowa's Center for Agriculture Safety and Health Annual Report, 2010

I-CASH is to enhance the health and safety of Iowa's agricultural community by establishing and coordinating prevention and education programs. This annual report gives information about a variety of areas that participate in I-CASH

Iowa's Center for Agriculture Safety and Health Annual Report, 2011

I-CASH is to enhance the health and safety of Iowa's agricultural community by establishing and coordinating prevention and education programs. This annual report gives information about a variety of areas that participate in I-CASH

Iowa's Center for Agriculture Safety and Health Annual Report, 2012

I-CASH is to enhance the health and safety of Iowa's agricultural community by establishing and coordinating prevention and education programs. This annual report gives information about a variety of areas that participate in I-CASH

Iowa's Center for Agriculture Safety and Health Annual Report, 2013

I-CASH is to enhance the health and safety of Iowa's agricultural community by establishing and coordinating prevention and education programs. This annual report gives information about a variety of areas that participate in I-CASH

Audit report on the Muscatine Agricultural Learning Center for the year ended December 31, 2013

Audit report on the Muscatine Agricultural Learning Center for the year ended December 31, 2013

Leopold Letter: A Newsletter of the Leopold Center for Sustainable Agriculture, November 2002

The Leopold Center was created by the Iowa Legislature as part of the Iowa Groundwater Protection Act of 1987. The Leopold Center believes contribute to a healthy ways of thinking about markets for Iowa farmers, a better understanding of local ecosystems, public policies and economic practices, and partnerships with consumers.

Leopold Center for Sustainable Agriculture, Annual Report 1997-1998

The Leopold Center was established by the Iowa Legislature as part of the Iowa Groundwater Protection Act of 1987. Its mandated missions are to identify impacts of agricultural practices, contribute to the development of profitable farming systems that conserve natural resources, and cooperate with Iowa State University Extension to inform the public of new findings.Information for this report was compiled by Leopold Center staff with the help of its researchers and educators who are committed to improving Iowa agriculture and the lives of Iowans.