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Galectin-8 binds HIV envelope glycoproteins with high affinity and promotes viral infectivity

Sheik-Khalil, Enas LU ; Kahl-Knutson, Barbro LU ; Johansson, Emil LU ; Karlson, Sara LU orcid ; Nilsson, Ulf J. LU orcid ; Leffler, Hakon LU and Jansson, Marianne LU (2026) In Frontiers in cellular and infection microbiology 16.
Abstract

Target cell entry of HIV-1 is dependent on the binding of gp120, the outer component of the viral envelope glycoprotein complex (Env), to CD4 and a coreceptor, preferentially CCR5 or CXCR4. Still, other interactions may also contribute to the infectivity of the virus. One such interaction is between the highly glycosylated gp120 and carbohydrate-binding proteins, such as galectins. Here, we studied the interaction between HIV-1 Env and a panel of galectins and found that galectin-8 (Gal-8), bound with highest affinity (K
D < 1µM) and also interacted with soluble CD4. Detailed analysis using probes for different parts of Gal-8 revealed that it was primarily the N-terminal carbohydrate recognition domain that interacted with HIV-1... (More)

Target cell entry of HIV-1 is dependent on the binding of gp120, the outer component of the viral envelope glycoprotein complex (Env), to CD4 and a coreceptor, preferentially CCR5 or CXCR4. Still, other interactions may also contribute to the infectivity of the virus. One such interaction is between the highly glycosylated gp120 and carbohydrate-binding proteins, such as galectins. Here, we studied the interaction between HIV-1 Env and a panel of galectins and found that galectin-8 (Gal-8), bound with highest affinity (K
D < 1µM) and also interacted with soluble CD4. Detailed analysis using probes for different parts of Gal-8 revealed that it was primarily the N-terminal carbohydrate recognition domain that interacted with HIV-1 Env expressing sialylated galactosides and both N- and O-linked glycans. Importantly, in cell cultures Gal-8 enhanced the infectivity of HIV-1, including strains with different coreceptor use and subtype origin, as well as HIV-2. This Gal-8 infectivity enhancement was particularly strong (up to 100-fold) at low virus inoculum doses. Next, we compared Gal-8 infectivity enhancement of primary HIV-1 isolates from people living with HIV at different stages of the infection. Of note, the infectivity of HIV-1 isolates obtained during the chronic, relatively immunocompetent phase, was significantly more enhanced by Gal-8 than isolates obtained at late-stage disease during severe immunodeficiency. Taken together, this study reveals novel carbohydrate dependent interactions between Gal-8 and HIV-1 Env, resulting in enhanced infectivity of HIV-1, with particularly strong effects at low dose exposure of strains circulating during the chronic infection phase. These results suggest that Gal-8 is a cell attachment protein that HIV-1 utilizes for optimized infectivity, which may guide the development of novel intervention strategies targeting this interaction.

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author
; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Humans, Galectins/metabolism, HIV-1/pathogenicity, HIV Envelope Protein gp120/metabolism, Protein Binding, CD4 Antigens/metabolism, Virus Internalization, HIV Infections/virology, env Gene Products, Human Immunodeficiency Virus/metabolism, Cell Line, HIV-2/metabolism, HEK293 Cells
in
Frontiers in cellular and infection microbiology
volume
16
article number
1801072
pages
15 pages
publisher
Frontiers Media S. A.
external identifiers
  • pmid:41987899
ISSN
2235-2988
DOI
10.3389/fcimb.2026.1801072
language
English
LU publication?
yes
additional info
Copyright © 2026 Sheik-Khalil, Kahl-Knutson, Johansson, Karlson, Nilsson, Leffler and Jansson.
id
de75487f-9fde-4514-b97e-d5f30d8f04a9
date added to LUP
2026-04-16 21:49:42
date last changed
2026-04-20 11:25:33
@article{de75487f-9fde-4514-b97e-d5f30d8f04a9,
  abstract     = {{<p>Target cell entry of HIV-1 is dependent on the binding of gp120, the outer component of the viral envelope glycoprotein complex (Env), to CD4 and a coreceptor, preferentially CCR5 or CXCR4. Still, other interactions may also contribute to the infectivity of the virus. One such interaction is between the highly glycosylated gp120 and carbohydrate-binding proteins, such as galectins. Here, we studied the interaction between HIV-1 Env and a panel of galectins and found that galectin-8 (Gal-8), bound with highest affinity (K<br>
 D &lt; 1µM) and also interacted with soluble CD4. Detailed analysis using probes for different parts of Gal-8 revealed that it was primarily the N-terminal carbohydrate recognition domain that interacted with HIV-1 Env expressing sialylated galactosides and both N- and O-linked glycans. Importantly, in cell cultures Gal-8 enhanced the infectivity of HIV-1, including strains with different coreceptor use and subtype origin, as well as HIV-2. This Gal-8 infectivity enhancement was particularly strong (up to 100-fold) at low virus inoculum doses. Next, we compared Gal-8 infectivity enhancement of primary HIV-1 isolates from people living with HIV at different stages of the infection. Of note, the infectivity of HIV-1 isolates obtained during the chronic, relatively immunocompetent phase, was significantly more enhanced by Gal-8 than isolates obtained at late-stage disease during severe immunodeficiency. Taken together, this study reveals novel carbohydrate dependent interactions between Gal-8 and HIV-1 Env, resulting in enhanced infectivity of HIV-1, with particularly strong effects at low dose exposure of strains circulating during the chronic infection phase. These results suggest that Gal-8 is a cell attachment protein that HIV-1 utilizes for optimized infectivity, which may guide the development of novel intervention strategies targeting this interaction.<br>
 </p>}},
  author       = {{Sheik-Khalil, Enas and Kahl-Knutson, Barbro and Johansson, Emil and Karlson, Sara and Nilsson, Ulf J. and Leffler, Hakon and Jansson, Marianne}},
  issn         = {{2235-2988}},
  keywords     = {{Humans; Galectins/metabolism; HIV-1/pathogenicity; HIV Envelope Protein gp120/metabolism; Protein Binding; CD4 Antigens/metabolism; Virus Internalization; HIV Infections/virology; env Gene Products, Human Immunodeficiency Virus/metabolism; Cell Line; HIV-2/metabolism; HEK293 Cells}},
  language     = {{eng}},
  publisher    = {{Frontiers Media S. A.}},
  series       = {{Frontiers in cellular and infection microbiology}},
  title        = {{Galectin-8 binds HIV envelope glycoproteins with high affinity and promotes viral infectivity}},
  url          = {{http://dx.doi.org/10.3389/fcimb.2026.1801072}},
  doi          = {{10.3389/fcimb.2026.1801072}},
  volume       = {{16}},
  year         = {{2026}},
}