There are no helper method that would render Infragistics controls. Please take a look at this page, it has detailed instructions of using Infragistics controls in MVC pages.
There are some limitations though. Infragistics doesn't have separate controls for MVC, they are simply making their asp.net controls available, but there's a drawback.
As long as you focus on areas of the controls that do not initiate post backs or rely on ViewState, you soon find many behaviors and functions that work perfectly in an ASP.NET MVC application.
Sample usage would be:
<%@ Register Assembly="Infragistics.Web.Mvc" Namespace="Infragistics.Web.Mvc" TagPrefix="cc1" %>
<%@ Register Assembly="Infragistics35.Web.v9.1, Version=9.1.20091.1015, Culture=neutral, PublicKeyToken=7dd5c3163f2cd0cb"
Namespace="Infragistics.Web.UI.GridControls" TagPrefix="ig" %>
<ig:WebDataGrid ID="wdg"
runat="server" Width="50%"
EnableViewState="false">
</ig:WebDataGrid>
No MVC helpers involved.