Kiessling is noted for her discovery of reverse transcriptase activity in normal human cells.[3] This report pioneered the importance of naturally occurring retrovirus sequences in human genes, now thought to be important to the genetic plasticity involved in human evolution and biology. Prior to this discovery, it had been assumed that reverse transcriptase was an enzyme found only in retroviruses (such as human immunodeficiency virus). To understand the normal biologic role of reverse transcriptase, Kiessling began to study eggs and early cleaving embryos.[4][5] Her dual interests in virology and reproductive biology led to research in semen transmission of human immunodeficiency virus, and the creation of the first laboratory for human in vitro fertilization in Oregon in the early 1980s. Harvard Medical School recruited Kiessling in 1985, where she conducted research until 2011.[6][7] Kiessling conducts research at the Bedford Stem Cell Research Foundation.[8]
The need to conduct biomedical research in areas not funded by the federal government led to the incorporation of the Bedford Stem Cell Research Foundation.[9] The techniques developed for the Special Program of Assisted Reproduction have been extended to other diseases of the male genitourinary tract, such as prostatitis and bladder infections. Expertise in human egg biology led Kiessling to develop the country's first human egg donor program for stem cell research in 2000. It remains a research focus today.[10] Kiessling's team was the first to establish the importance to circadian rhythms to early egg development.[citation needed]
Among the publications by Kiessling is the first comprehensive look at the influence of accurate science terminology on laws titled, "What is an Embryo," published by the Connecticut Law Review [11] along with rejoinders by Harold Shapiro, Prof John A. Robertson, Prof. Lars Noah, and Father Kevin P. Quinn. The law review addresses the controversy of all of the entities that are currently called embryos with regards to embryonic stem cell research legislation around the world.[12] In 2003, Kiessling wrote Human Embryonic Stem Cells: An Introduction to the Science and Therapeutic Potential, the first textbook on the controversial topic.[13]
In March 2020, Kiessling expanded her laboratory operations at the Bedford Research Foundation to include SARS2 (COVID-19) testing.[17] On April 17, 2020, Kiessling reported that one of her daughters, a front-line worker at a local hospital, had tested positive for Coronavirus.[18] Kiessling's frustration over the continued lack of available testing led her to expand the Foundation's SARS2 testing efforts to offer public testing.[19]
2014 – Honorary Doctorate and Lifetime Achievement Award from Jodhpur School of Public Health, Mumbai, India, presented at the 2014 HIV Congress in Mumbai.[24]
2014 – Oregon State University Commencement Address[25][26]
2014 – Honorary Doctorate in Cell and Molecular Biology, Oregon State University[27]
Kiessling, Ann A.; Anderson, Scott (2003). Human Embryonic Stem Cells: An Introduction to the Science and Therapeutic Potential. Burlington, MA: Jones and Bartlett Publishers, Inc. ISBN978-0763723415.
Kiessling AA (2004). "What is an embryo?". Connecticut Law Review. 36 (4): 1051–92. PMID15868674.