title: Inhibition of human immunodeficiency virus type 1 by lactic acid bacteria from human breastmilk.
abstract: BACKGROUND
  Human breastmilk provides a rich source of commensal lactic acid bacteria (LAB) to the infant during breastfeeding and stimulates abundant growth and colonization of these bacteria at mucosal surfaces in the infant gastrointestinal tract. While conferring critical nutritional and immunologic support to the developing newborn, breastmilk also serves as a vehicle for human immunodeficiency virus type 1 (HIV-1) transmission from mother to child during breastfeeding. Whether breastmilk LAB confer protection against mucosal exposure to HIV-1 in breastfeeding infants is unknown.
  
  
  METHODS
  In the present study, we sought to evaluate LAB isolated from the breastmilk of healthy women for the ability to inhibit HIV-1 infection in vitro. A total of 38 strains of breastmilk bacteria were evaluated in this study. Both heat-killed bacteria and cell-free conditioned supernatants from bacterial cultures were tested for the ability to inhibit infection with HIV-1 using viral isolates with tropism for CCR5 (R5), CXCR4 (X4), or R5/X4 dual-tropism.
  
  
  RESULTS
  Significant inhibition of R5-tropic HIV-1 was demonstrated using heat-killed bacteria, most notably among breastmilk strains of Lactobacillus and Pediococcus. Selected strains of breastmilk LAB also demonstrated significant inhibition of HIV-1 infection against virus with tropism for X4 and R5/X4.
  
  
  CONCLUSIONS
  These results demonstrate for the first time that commensal LAB from human breastmilk inhibit HIV-1 infection in vitro and suggest a possible role for these bacteria in mucosal protection against HIV-1 in the breastfeeding infant.
authors.affiliation: Department of Nutrition, Food Science, and Technology, Complutense University of Madrid, Spain.
authors.forename: Virginia
authors.initials: V
authors.lastname: Martín
authors.forename: Antonio
authors.initials: A
authors.lastname: Maldonado
authors.forename: Leónides
authors.initials: L
authors.lastname: Fernández
authors.forename: Juan M
authors.initials: JM
authors.lastname: Rodríguez
authors.forename: Ruth I
authors.initials: RI
authors.lastname: Connor
mesh_terms: D002478:Cells, Cultured; D015658:HIV Infections / Q000517:prevention & control / Q000635:transmission*; D015497:HIV-1 / Q000254:growth & development*; D006801:Humans; D018445:Infectious Disease Transmission, Vertical / Q000517:prevention & control; D007413:Intestinal Mucosa / Q000821:virology; D007778:Lactobacillus / Q000502:physiology*; D008895:Milk, Human / Q000821:virology*; D019713:Receptors, CCR5 / Q000378:metabolism; D019718:Receptors, CXCR4 / Q000378:metabolism; D038301:Virus Inactivation
chemical_list: D019713:Receptors, CCR5; D019718:Receptors, CXCR4