title: Treatment with polyclonal immunoglobulin during T-cell reconstitution promotes naive T-cell proliferation.
abstract: Natural antibodies are unique self molecules endowed with both suppressive and activating functions on various cells of the immune system and are recognized as a fundamental link between the adaptive and innate immune system. Here, we examine the role of natural antibodies, using polyclonal immunoglobulins (Ig), as a promoter of T-cell reconstitution in a context of lymphopenia. We have established a mouse model to mimic immunologic recovery in adult patients with severe hypothymic function subjected to autologous hematopoietic precursor cell transplantation. Thymectomized mice were transplanted and treated with low doses of Ig or its Fab or Fc fragments. The animals displayed, during early phases of Ig treatment, a significant increase of T-cell reconstitution displaying a naive CD4(+) phenotype. In addition, the Ig-treated animals exhibited an increase dilution of single-joint T-cell receptor excision circles (sjTRECs) in peripheral blood, suggesting an early increase in proliferation of T cells stimulated by the natural antibodies. These results unveil a novel and considerable effect of intravenous Ig treatment in situations of severe lymphopenia as a stimulator of proliferation of peripheral naive T cells, possibly protecting diverse immune repertoires.
authors.affiliation: Instituto Gulbenkian Ciência, Immune Reconstitution-External Group, Rua da Quinta Grande, Oeiras, Portugal. elisabete.pires@ineti.pt
authors.forename: Ana Elisabete
authors.initials: AE
authors.lastname: Pires
authors.forename: Ana Filipa
authors.initials: AF
authors.lastname: Afonso
authors.forename: Ana
authors.initials: A
authors.lastname: Queirós
authors.forename: Maria Salomé
authors.initials: MS
authors.lastname: Cabral
authors.forename: Luis
authors.initials: L
authors.lastname: Porrata
authors.forename: Svetomir N
authors.initials: SN
authors.lastname: Markovic
authors.forename: Srini V
authors.initials: SV
authors.lastname: Kaveri
authors.forename: Maria Gomes
authors.initials: MG
authors.lastname: da Silva
authors.forename: Cristina
authors.initials: C
authors.lastname: João
mesh_terms: D000328:Adult; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D049109:Cell Proliferation / Q000187:drug effects; D004195:Disease Models, Animal; D005260:Female; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D007128:Immunoglobulin Fragments / Q000008:administration & dosage*; D016756:Immunoglobulins, Intravenous / Q000008:administration & dosage*; D007156:Immunologic Memory; D008231:Lymphopenia / Q000276:immunology / Q000628:therapy; D051379:Mice; D008807:Mice, Inbred BALB C; D011948:Receptors, Antigen, T-Cell / Q000235:genetics / Q000378:metabolism; D016176:T-Lymphocyte Subsets / Q000187:drug effects / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D013934:Thymectomy; D014182:Transplantation, Autologous
chemical_list: D007128:Immunoglobulin Fragments; D016756:Immunoglobulins, Intravenous; D011948:Receptors, Antigen, T-Cell