Induction of pre-B cell proliferation after de novo synthesis of the pre-B cell receptor

The assembly of a pre-B cell receptor (pre-BCR) composed of an Ig μ heavy chain (μH-chain), the surrogate light (SL) chain, and the Igα/β dimer is critical for late pro-B cells to advance to the pre-B cell stage. By using a transgenic mouse model, in which μH-chain synthesis is solely driven by a tetracycline-controlled transactivator, we show that de novo synthesis of μH-chain in transgenic pro-B cells not only induces differentiation but also proliferation. This positive effect of μH-chain synthesis on proliferation requires the presence of SL chain and costimulatory signals provided by stromal cells or IL-7. We conclude that pre-BCR signaling induces clonal expansion of early pre-B cells.

B lymphocyte-restricted expression of prion protein does not enable prion replication in prion protein knockout mice

Prion replication in spleen and neuroinvasion after i.p. inoculation of mice is impaired in forms of immunodeficiency where mature B lymphocytes are lacking. In spleens of wild-type mice, infectivity is associated with B and T lymphocytes and stroma but not with circulating lymphocytes. We generated transgenic prion protein knockout mice overexpressing prion protein in B lymphocytes and found that they failed to accumulate prions in spleen after i.p. inoculation. We conclude that splenic B lymphocytes are not prion-replication competent and that they acquire prions from other cells, most likely follicular dendritic cells with which they closely associate and whose maturation depends on them.

Phytochrome B Affects the Levels of a Graft-Transmissible Signal Involved in Tuberization1

Grafting experiments between phytochrome B antisense and wild-type potato (Solanum tuberosum L. subsp. andigena [line 7540]) plants provide evidence that phytochrome B is involved in the production of a graft-transmissible inhibitor of tuberization, the level of which is reduced in the antisense plants, allowing them to tuberize in noninducing photoperiods.

Viral dynamics in hepatitis B virus infection.

Treatment of chronic hepatitis B virus (HBV) infections with the reverse transcriptase inhibitor lamivudine leads to a rapid decline in plasma viremia and provides estimates for crucial kinetic constants of HBV replication. We find that in persistently infected patients, HBV particles are cleared from the plasma with a half-life of approximately 1.0 day, which implies a 50% daily turnover of the free virus population. Total viral release into the periphery is approximately 10(11) virus particles per day. Although we have no direct measurement of the infected cell mass, we can estimate the turnover rate of these cells in two ways: (i) by comparing the rate of viral production before and after therapy or (ii) from the decline of hepatitis B antigen during treatment. These two independent methods give equivalent results: we find a wide distribution of half-lives for virus-producing cells, ranging from 10 to 100 days in different patients, which may reflect differences in rates of lysis of infected cells by immune responses. Our analysis provides a quantitative understanding of HBV replication dynamics in vivo and has implications for the optimal timing of drug treatment and immunotherapy in chronic HBV infection. This study also represents a comparison for recent findings on the dynamics of human immunodeficiency virus (HIV) infection. The total daily production of plasma virus is, on average, higher in chronic HBV carriers than in HIV-infected patients, but the half-life of virus-producing cells is much shorter in HIV. Most strikingly, there is no indication of drug resistance in HBV-infected patients treated for up to 24 weeks.

Payment order for Thomas Adams, 1785 June 30

Handwritten order to John Sale to pay scholarship funds to student Thomas Adams (Harvard AB 1788), signed by signed by Charles Chauncey, John Clarke, Jonathan Williams, and James Thwing.

Payment order for Ephraim Eliot on behalf of Thomas Adams, 1786 June 28

Handwritten order to John Sale to pay the bearer the specified amount signed by Charles Chauncey, John Clarke, Jonathan Williams, and James Thwing. The verso is signed by Ephraim Eliot on behalf of student Thomas Adams (Harvard AB 1788).

Draft of letter from Loammi Baldwin to Thomas Gill, 1836 September 23

A half-page handwritten draft of a letter to Thomas Gill written on the second leaf of a September 10, 1836 printed circular from Gill requesting copies of those who made speeches at the second Centennial Anniversary.

Power of Attorney, Samuel Shapleigh for Thomas Adams, Jan. 12, 1791

Signed by Thomas Adams and witnessed by Abraham Biglow and Daniel Clarke Sanders.

Power of Attorney, Samuel Shapleigh for Thomas Thompson, May 18, 1791

Signed by Thomas Thompson and witnessed by Thaddeus Mason Harris and Otis(?) Clarke.

Letter from Thomas Hollis to the Curators of Harvard College, 1762 July 21

Thomas Hollis V (1720-1774), widely known as Thomas Hollis of Lincoln’s Inn, was a very generous donor to Harvard College, particularly its library. This letter, which appears to have accompanied a package, demonstrates that he also donated prints to the College. Hollis wrote: "N.B. the Ludlow, Sydney, Marvell, & Cleopatra are struck on paper made from white & colored silk rags, the produce of premiums of the Society, the noble Society for promoting arts & commerce."

Diary of Thomas Marsh, 1751

Diary kept in an interleaved almanac from 1751. Entries in the diary are brief and sporadic, recording events including travel, visitors, weather, sermons heard, holidays, illnesses and deaths. Occasional expenses are noted, including ones for hay, cider, bottles, shoes, and doctoring. A few dates of college events are noted, including the semi-annual Corporation meeting and Commencement. On the last page is a list of student names, presumably those tutored by Marsh.

Letter from John Quincy Adams to his brother, Thomas Boylston Adams, 1786 July 2

This letter was written by John Quincy Adams on July 2, 1786 to his younger brother, Thomas Boylston Adams, who was then staying with their uncle, the Reverend John Shaw, in Haverhill, Massachusetts. In the letter, John gives Thomas advice on life as a student at Harvard, instructing him to choose his friends carefully, to favor those who are virtuous and studious over those who are idle and prone to vice, to maintain an "unblemished moral reputation," and to spend as much as six hours each day studying in order to excel as a scholar.

Letters from Thomas James Maling to William Tudor,

Six letters providing information about British naval vessels and news of the movements of French vessels and South American belligerents. He also mentions the silver mining partnership and the agent B. Llaveria. Included are a letter from Maling’s wife, and one letter from Maling in Spanish

Letters from Thomas James Maling to William Tudor,

Four letters regarding the conflicts in South America, including the movements of military leaders Juan Manuel de Rosas, Juan Lavalle, and Simón Bolívar, as well as politics in Europe. Also included are mentions of communication with B. Llaveria, the agent for supplying the silver mining operation.